I run Debian on a small file server in my parent's house. Granted I had to set it up for them, but after configuring unattended upgrades, I only needed to work

I run Debian on a small file server in my parent's house. Granted I had to set it up for them, but after configuring unattended upgrades, I only needed to work on it to upgrade from Debian 8 to 10 because it was getting close to being EOL. I keep SSH open to the internet in case I need to troubleshoot something. Their computers automatically run weekly incremental backups and it's transparent to them. It's not the best solution, but it works reasonably well with little maintenance on my part. On Windows you can set a smb drive to mount automatically at boot and it'll behave like a normal drive. So it was easy to explain to them that you can access that folder from both machines simultaneously. I agree that this is not a good solution for someone that has to set it up themselves. In that case I'd recommend something like a Synology unit.