Backup. I use Backblaze personal which is $179 for two years of ‘unlimited’ storage. All my important self hosted data is duped to some old 2.5" external drives connected to my work machine that then is backing up to Backblaze. I also have 1yr retention, so any deleted file is accessible for up to 1yr.

After backups are sorted, stick with the OS you know best. If Windows (I hope not), then HyperV for VMs is good. Try the official Nextcloud VM from Hanson IT. Nextcloud is a good catch-all, but it’s beaten by other specific tools. I now host all I need from specific Docker containers: photos, calendar, email backup etc etc

But I would say Docker. Docker desktop if Macos or Windows if your thing. Get to know docker and the world of self hosting is your oyster.

As what others say, keep it all to your home network and tread carefully when trying to remote access it all.