Today my wife and I made the switch from Microsoft Office 365 + Onedrive to the MyKsuite with Joplin as onenote alternative, Thunderbird for Outlook, and LibreOffice as desktop replacements. Feels great! It’ll take a while for the Microsoft email to become unused, but we’re getting there!
Ksuite is based in Switzerland and 1TB cloud storage plus their email and office apps costs €1.19 per month per user, an absolute steal compared to M365.
Next up: Linux as OS, probably a dual boot.
Just make sure your custom domain registrar is using a different email from your custom domain or you might run into a support nightmare.