xrandr is Xorg only, it doesn't work with Wayland. You should be able to make SDDM use your Plasma display configuration - https://wiki.archlinux.org/title/SDDM#Match_Plasma_display_configuration
No clue if that's going to fix your issues, but at least it's supposed to work with Wayland.
Right, now get a borderline computer-illiterate person to connect to your network, ensure their firewall isn't misconfigured to block all incoming traffic (with TeamViewer, this configuration would still work because the device just connects to the TV server) and open and set up a completely separate screen sharing program.
I know none of these steps are difficult if you have any idea what you're doing, but I've met plenty of people who would most likely need assistance going through the motions. Funnily enough, the best way to do it remotely would probably be to get them to install TeamViewer to then set this up for them remotely.
By the way, as far as networking goes, Tailscale does the same thing TeamViewer does, just for a VPN instead of a screen sharing application - it will try to do all the NAT punchthrough techniques and IPv6 connection and fall back on tunneling through relay servers if all else fails. It's not any more of a direct connection than TV.
So I did look more into it, and apparently the open firmware is technically compatible with PCIe cards using this chip, but doesn't provide any advantages over just wiping the firmware and letting the chip default to its built-in fallback firmware, and so the maintainer doesn't see any value in explicitly supporting it.
Now the question is whether you consider the proprietary fallback firmware to be acceptable to run - this might sound weird, but for example FSF has explicitly made exceptions for devices with built-in firmware to be able to qualify for the Respects Your Freedom certification, so if your view aligns with theirs, you might consider this to be completely OK. If not, the free firmware appears to have a similar feature set, you'll just have to jump through more hoops.
Also do note that both the fallback firmware and the free firmware are missing many features of the proprietary firmware, so make sure to check it's not missing anything you need (wake on LAN, Jumbo frames and PXE boot seem like the most notable missing features to me).
Convenience (after you install it, all you have to do is enter the code and you're connected, no other setup required), familiarity (it's the default name people will think of or find if they want remote access - that alone means they can get away with pushing their users slightly more) and - IMHO most importantly - connectivity: if two computers can connect to the TeamViewer servers, they will be able to connect to each other.
That's huge in the world of broken Internet where peer to peer networking feels like rocket science - pretty much every consumer device will be sitting behind a NAT, which means "just connecting" is not possible. You can set up port forwarding (either manually or automatically using UPnP, which is its own bag of problems), or you can use IPv6 (which appears to be currently available to roughly 40% users globally; to use it, both sides need to have functional IPv6), or you can try various NAT traversal techniques (which only work with certain kinds of NAT and always require a coordinating server to pull off - this is one of the functions provided by TeamViewer servers). Oh, and if you're behind CGNAT (a kind of NAT used by internet providers; apparently it's moderately common), then neither port forwarding or NAT traversal are possible. So if both sides are behind CGNAT and at least one doesn't have IPv6, establishing a direct link is impossible.
With a relay server (like TeamViewer provides), you don't have to worry about being unable to connect - it will try to get you a direct link, but if that fails, it will just act as a tunnel and pass the data between both devices.
Sure, you can self host all this, but that takes time and effort to do right. And if your ISP happens to use CGNAT, that means renting a VPS because you can't host it at home. With TeamViewer, you're paying for someone else to worry about all that (and pay for the servers that coordinate NAT traversal and relay data, and their internet bandwidth, neither of which is free).
It's less about the computer and more about the card itself - Talos II and Blackbird both use the BCM5719 chip for their integrated NICs. Basically, you're flashing part of the motherboard with this firmware. A PCIe card built around the same chip might connect the interfaces in a different way, and firmware doesn't generally have a way of poking around to find out how everything's set up from the hardware side of things - it needs to just know this, and that's why there are separate firmware builds for different hardware.
If you flash one of these files to that card, it might just so happen to work perfectly, but it most likely won't. You would need to figure out how it's wired up and modify the firmware with that knowledge. And then you could use the modified open firmware with that specific card model on any computer that supports the proprietary firmware, because IIUC this is meant to be functionally identical.
So in short, no, you cannot currently use this open firmware on any computer other than Talos II and Blackbird, but for slightly different reason than you might think.
Also, the Arch repos are pretty much just an "AUR with binaries" - they contain the same PKGBUILD files used by AUR packages, because that's how Arch packages are built. So you can just download an Arch package PKGBUILD, modify it however you wish, and then build and install it.
If it is an Arch-based distro (sorry, I don't recognize the package manager), then this might just be the recent Wine update that made it 700 MB smaller (which would mean the rest of your system grew 300 MB)
I made a post here about it: this one
Btw, is there a way to link to a post in a way that resolves on everyone's separate instance instead of hard coding it to my instance?
Also, some programs, such as many terminal emulators, can cache you PW so you don't have to enter it multiple times.
Terminal emulators don't (or at least shouldn't) do any such thing. sudo itself is responsible for letting you do privilege escalation without password for some time after successfully passing once - whenever you run it and successfully authenticate, it saves your user id, current time and a session identifier (each open shell gets a unique identifier) into a file. Then, when you attempt to do anything, it will check this file to see if you've if you've authenticated within the last few minutes in this terminal, and only ask for a password if you haven't.
For more info, see man sudoers_timestamp
I've explained my reasoning for all the points I disagree with. Which one do you have a problem with? CS:GO? The last version of CS:GO is still available on Steam and fully playable, the only missing part is matchmaking servers - you can play with bots or on third party servers without any problems. That seems far from gone.
CS:GO got a controversial update and got renamed. Old versions are still available under CS2, you just can't use Valve's servers anymore. Playing old versions on private servers is possible. But OK, I give you half a point for this one - you can't play matchmaking with old smoke physics anymore (but then again, it's not like it's the first CS:GO update to change the gameplay in a fundamental way).
Moving on, Artifact. It's in my library, ready to be played - Valve definitely didn't "make me lose Artifact" like you claimed. The community is dead, but there are still 40 people playing right now according to SteamDB and servers are up. One point down for easily verifiable lie.
And finally, Team Fortress 1. I assume you don't mean the Valve's game called Team Fortress Classic, because that one is still available for purchase on the Steam Store and oscillates between 40 and 100 active players at any time. So that leaves us with Team Fortress, a mod for Quake. But that one is available from ModDB without any problems, so... What's the issue supposed to be, exactly? No points, because I have no idea if there's more to your claim.
Hint: blatantly lying about some points heavily undermines the other points you make. So at least try to be subtle.
It should not be controlled by a company that is known to make you lose your games.
Are you referring to the fact that Valve promotes digital game distribution (which is a very fair view), or are you talking about some incident where Valve removed games from people's libraries? Because if it's the second one, then I would really like to hear about it.
Maybe Redis/Redict? The development on that seems pretty dead.