To replace everything. Mail, calendar, drive, vpn, password manager, documents etc. What are the pros and cons relative to proton? What are the mobile apps like? What assurances do you have they won’t go full proton in the future? And other questions
I can second most of the suggestions. I do not host an office suite (for now?) but I am syncing my keepass dbs over syncthing along with my notes and important documents. I think since 2016 or so. It works well.
Before I had a server I just synced them in a triangle between my phone, laptop and desktop. Most things had 3 copies this way. Any device could offload changes to another. Now I have a central node and the option to sync as before if the server is down. With Tailscale, I don’t need to be on the same wifi now eiter.
The keepassDX limitations are not a big deal if all you need is basic autofill.
Mail providers are hard to chose. I am leaving proton for the lack of easy smtp and their locked in nature. Get your oen domain and you will be able to switch more easily in the future.