I wouldn’t actually selfhost email, it’s not particularly easy and there are many issues you will probably encounter. I recommend ProtonMail, it’s $3.50/month if you only need email and for $8/month you also get calendar, cloud storage, a password manager and a great VPN. Also, they are very focused on privacy and encryption and their apps are open source. Alternatively you can go with IVPN or Mullvad, both are great. Digitalocean has been fine in my experience, have you had any issues with it?

Damn, fuck Windows. Fortunately I don’t have to use it.

The ONLY DNS server you should have set on your network is a/the PiHole(s).

That’s exactly what I do, since I never had any stability issues with my Pihole.

Windows calls them ‘preferred’ and ‘alternate’ DNS servers. That roughly translates to primary/secondary.

Use something like AdGuard or NextDNS as your secondary resolver

Check out the comment by @AtariDump@lemmy.world