Protonmail–I’ve used them for my custom domain email for the last 4 years and have had very few problems (other than needing to recompile the Protonmail Bridge app so I could use it on an ARM server)–I think I pay around $50/year. I selfhost Nextcloud for everything else (files, calendar, news, etc.)
Do you have any tips using KDE Connect with a local VPN (Wireguard)? It works great for me on the same network, but unfortunately fails to connect outside of my network despite one (or both) devices connected to my VPN