Totally fine. Note however that this isn't marketed as a place for anyones most private thoughts, it is right there in the announcement:
> unique collaboration system that is optimized for granular sharing between individuals rather than "all-in" sharing amongst teams or specific groups
Such applications has their place and for what you know I might be using them myself, but don't for a second believe that any web application with sharing possibilities are a place for anyones most private thoughts.
If you did think so until today, take my advice and clean up everything that can get you in hot water.
Someone funny once said: "what happens on the internet stays on the internet, forever". This is worth reminding oneselves about.
Edit: if one needs sync and security one can maybe use something like Joplin which supports encryption. I haven't verified neither the crypto nor the general codebase nor if it can autoupdate. I'm just saying it might be possible as an individual to sync sensitive data somewhat securely like people think they do with online services but if you are at a level where E2EE is necessary and where government agencies or basically (in my opinion) anything more than snooping kids or coworkers enters the picture, my advice is to forget about web applications.
To avoid doing what I despise when others do, when they basically say "if you don't do everything correct you can just give up": That does not mean you necessarily have to give up your current solution:
Just be realistic about what threat models it can hold up against.
Edit 2: (as said elsewhere) E2E-encryption is seriously nice and I can pay a premium for it even if I don't feel I need it. Just know what it helps against. And don't tell others that everything else is trash and unusable (but feel free to tell them what the risks are and how to protect oneselves).