Selfhosted

For files I just use WebDAV that's built in to Apache. It's really not fancy, but does all I need.

I agree. Nextcloud is not so great. It does too many things. It's still OK to use it, because it replaces file sharing in the cloud and you can have your own addressbook or contacts without sacrificing privacy in the Google cloud.

Nothing special. It just runs and updates well. It also tells you what you forgot to do.

I thought about using a dedicated addressbook, calendar and file sharing, but I'd need to have some time and at the moment it's just running without headaches.

I didn't know anything about docker when I set up my NC years ago, so I ran it as a snap on bare metal. Man, it's gotten so much better! It used to really suck. Like, simple file transfers just didn't work half the time, so I'd be retrying the same thing over and over... A few years ago, I literally migrated it from bare metal to a VM, but kept the exact same install. I have so much crap on it now, I think I'll never bother switching it out to docker, just because of the inconvenience. I know the snap version can just run using a local hostname, you just have to set it in trusted domains setting. Might be the same in the docker image?

Does this help, OP?

https://selfh.st/apps/?tag=File+Management

I would suggest looking at Syncthing. It's not perfect by any stretch, but it works peer to peer, without any kind of central host, ip or domain name requirements. You simply install it on the client machines, and they work out how to talk to each other over any available networks.

Beware changing the casing on your files or directories though, Syncthing was made entirely case sensitive, which does not play nice with Windows.

One very nice feature is that it does have an android client (https://f-droid.org/en/packages/com.github.catfriend1.syncthingandroid/), and it supports full background syncing to your local storage on the phone. Great for syncing your photos, but also music. You add some mp3's on your desktop computer, and by the time you've put on your jacket they're on your phone ready to listen to without any 'service' getting in your way.

A more advanced tip; Get a VPS somewhere in the cloud with cheap storage, and have Syncthing on it listening on port 443. That will allow syncing in more restrictive corporate settings, which often don't allow connections to port 22000. And it gives you a 'cloud backup' of your important files in one go.

For just files I'd use Syncthing or Resilio (I keep hundreds of gigs synced with ST). Resilio has a feature that's very useful - Selective Sync. This allows you to setup a sync job that syncs the index of files, but doesn't sync the actual files until you select a file(s) to sync on the remote device. I use this to access my media files from anywhere (3TB) which I obviously don't want to try to sync the entire folder to my phone, etc.

But since you effectively are on the same LAN, you can use any file copy tool the respective OS's support.

Though for WAN connections, I prefer tools with some redundancy/resilience, since those connections can be slow or experience drops, and regular copy tools aren't designed to contend with that (in Windows the only tool I can think of off hand is Robocopy, but I think Teracopy will at least show you if a file copy fails).

It really depends on your use-case, what you're trying to solve for.