I use syncthing for some of my “can-never-lose-these” files. syncthing synchronizes files between different devices. This is not an online-file-hosting thing like Google Drive or OneDrive. These files are physically present on all synchronized devices.
My server is the “main” (you can make everyone equal) syncthing every other syncthing connects to. With an established connection, files will be synchronized on participating devices. AFAIK, syncthing is compatible with Windows, Android and Linux.
This way, my important files are on my server, my smartphone, my PC and my laptop and every single one of these devices must simultaniously explode for me to lose my data. Also, it’s on docker hub
pi-hole is another great one. Local adblocker for the whole network, just set it as your DNS server or let the DHCP server propagate this DNS server to your clients. This too is on docker hub
Yeah, I do daily VM-backups which include all of the data on syncthing. No matter what you have, you always gotta have a good backup-strategy.