For what it's worth, though, you can proxy other services, like Gemini or gopher, through the same proxy for simplicity's sake.
K3can
I self host.
I use nginx as a reverse proxy with crowdsec. The backends are nginx and mariadb. Everything is running on Debian VMs or LXCs with apparmor profiles and it's all isolated to an "untrusted" VLAN.
It's obviously still "safer" to have someone else host your stuff, like a VPS or Github Pages, etc, but I enjoy selfhosting and I feel like I've mitigated most of the risk.
I'd imagine that if your job is making YouTube videos, portainer and other graphical abstraction layers probably make more visually interesting videos than just watching someone type out a bunch of commands.
If you're going to be playing with custom locations and such, it might be worth using nginx directly instead of through the limitations of NPM.
I know I'm a bit late to the conversation, so I don't know if this is still helpful... But I have a camera with "AI Detection" built into it and it appears to send alerts via its ONVIF connection. I've disabled motion and other detectors on my NVR (AgentNVR) and instead configured it to just wait for an alert from the camera itself to start recording. It's been working quite well.
My initial plan was to use a coral TPU and frigate, but the Coral/Gasket drivers appear to be pretty old and I couldn't get them to work properly, myself.
I've also been running nginx in an unprivileged LXC container. I haven't used fail2ban, specifically, but crowdsec has been working without issue.
You can mostly just treat an LXC like a normal VM.
I mostly learn from mistakes, and since homelabs are all about learning, there are bound to be mistakes.
I've borked my network multiple times, broken VMs, and redesigned things from the ground up, again.
Big lesson is to have backups. Lol
On a pi, specifically?
Mine is currently running Mailrise and serving as a qdevice for Proxmox. It used to run nginx as a reverse proxy, but I moved that to a different machine. I had a second pi specifically for sharing USB devices over the network, but I wasn't using it very much so it's currently not in use.
If you're looking for general ideas, I think a pi would make a good appliance for ddclient, Homepage/Dashy, an SSH/VPN jumpbox, UPS monitoring, or a notification platform. Basically, any set-and-forgot service that you want to keep running 24/7.
I know you said you decided against it, but perhaps reconsider USB?
I was facing the same dilemma a few months ago, and ultimately decided that trying to break out those internal connections wasn't worth it. The problem with these tiny PCS is that they are not designed with arrays of drives in mind. There's typically not enough room in the case to properly add an additional drive, so you end up running the sata cord through a hole in the case and using an external drive and power supply anyway.
USB on the other hand, is intended to connect to an external device. The connectors themselves are more robust and they can even supply power.
I use my external drive for data I don't have to access constantly, like templates and backups. 90% of the time it's just sitting in standby. If you need to access a lot of data constantly, you might start to notice the slower USB speeds; if you can segment your data, keeping your "working" files on the internal drive and just use the external for storage, you probably won't notice the USB at all. It's certainly not the perfect solution, but with your particular restrictions, it might be the better tool for the job.
The other option would be Network Attached Storage, essentially a low power computer that just exists to allow other computers to access its storage. You can probably find an old, cheap desktop PC for sale locally, likely for less than it would cost you to bring out those internal ports and buy a drive enclosure and power supply.
I'm using cloudflare as my nameserver and the free API seems to work just fine with ddclient.
I do occasional smaller "takeouts" and haven't had any issues.
I have an "automatic album" (or whatever they call it) where all the photos of friends and family (even pets) get automatically added to it. Then I can just request a "takeout" for that one album, since those are the photos I actually care about. It's a much smaller download than the entirety of my Photos account.
I use podman almost exclusively at this point. I like having the rootless containers and secrets management. If you're on Debian, though, I strongly suggest pulling podman from Trixie. The version in Bookworm is very out of date and there's been a lot of fixes since then.