Do NOT self-host email! In the long run, you’ll forget a security patch, someone breaches your server, blasts out spam and you’ll end up on every blacklist imaginable with your domain and server.

Buy a domain, DON’T use GoDaddy, they are bastards. I’d suggest OVH for European domains or Cloudflare for international ones.

After you have your domain, register with “Microsoft 365” or “Google Workspace” (I’d avoid Google, they don’t have a stable offering) or any other E-Mail-Provider that allows custom domains.

Follow their instructions on how to connect your domain to their service (a few MX and TXT records usually suffice) and you’re done.

After that, you can spin up a VPS and try out new stuff and connect it also to your domain (A and CNAMR records).

Media Server? No content backup at all.

If you lose everything, just download new stuff you want to watch, or redownload a few TV series/movies.

Music? There are streaming services.

Only backup configurations and maybe application data, so that the reinstall will be easy. Those few kB/MB could sit anywhere. I’m using GitLab for this purpose.

Edit: Images! If you have your photos on there, back them up! They can’t be replaced!