lol, Microslop shooting themselves in the foot once again. At this point people will move to MacOS or Linux because so much damage to their brand can’t simply be ignored anymore.
Use Docker Compose and put Caddy in front of it for HTTPS. For backups the easy way is to just git pull your repos via cron on some remote systems. Or use syncthing to also move the server configs over. For the runner, 1 GB RPi 4 should be fine for many situations. It can compile and run many Rust/Python tests fine or build static sites. You could also setup an old x86 next to it (this is essentially what GitHub Runners are too: old x86 cpu’s).