Not sure if you find NextCloud too fat for your solution, I dont bother about its <= 100MB size ?
Of course, this is so much more, than a simple note taker.
But this is small, perfectly maintained, has smooth update process, gives full control over all aspects of sharing, accounts, and so on, has free apps, WebDAV support, offers an API access, runs on a simple, virtual PHP server ...
Notes can be edited as MarkDown ( as one of the simplest options ), with Online editor and good-working Apps available.
I'm still testing and dive deeper and deeper into NextCloud for my personal and private small teams, and this is veeeery smooth so far.
Probably, you like and get more familiar with that too