I’ll just point out since you highlighted encryption as a selling point for those unaware: Tutanota was court order to build a backdoor against one of their users. Not trying to blame Tutanota specifically, just saying relying on a third part to do the encryption for you is not bulletproof no matter how impressive the encryption sounds.

I used it for a bit and enjoyed how well developed it is, but I moved onto something different as I needed something more freeform. If the structure of BookStack works for you, you can’t get much better.

Try putting an RSS reader on their like FreshRSS! Or a bookmark manager such as LinkAce! Start your own personal wiki/knowledge base with BookStack! Try deploying them natively, then learn how awesome docker is and put them into a compose file. Add wireguard into the mix so your services can only be accessed via a VPN.

Now get yourself a domain if you don’t already have one. Pro tip if you want to maximize the cheapness of your setup, you can get a .xyz domain for .99 cents a year! Just has to be funny numbers, but find some numbers that has meaning and its not bad. Now that you have a domain, put those bad boys in a subdomain. Tired of those pesky browser errors? Time to setup a reverse proxy and get yourself an HTTPS cert. Caddy is brain dead easy to do this.