Nextcloud contacts gives you CardDav, so it works with Android, iOS, and any number of Linux/Windows/Mac clients. Thunderbird certainly, and many other desktop mail clients. (Don’t know about a Linux or Windows app limited to just contact management over CardDav, but it’s probably out there.)

This book is amazing. Every other resource I find refers back to Michael Bazzell as the expert.

Check out Pangolin with a cheap Racknerd VPS. More info over in c/selfhosted@lemmy.world

https://lemmy.sdf.org/post/35616968

If you use Office 365 web version of Word and Excel, you can use that in a Linux browser; no Windows needed.

Look up Unicode Fraktur characters