I've previously bounced between different open-source notetaking apps but the great thing about any note format based on Markdown (Standard Notes/Obsidian/Zim/etc), is that it's pretty easy to move from one platform to another if they stop being maintained.
Although in the end I ended up with Microsoft OneNote (with Obsidian for special cases), Microsoft isn't going away and they don't have a habit of killing core products like Google does.
Yes. I almost settled on Microsoft OneNote. I just don't like several things of it. The writing and reading experience is not great. And I constantly find I really need one note to belong to multiple categories, but OneNote forces me to think where to save a note (which leaves me writing fewer notes).
A solution to that is to have a fleeting / unfiled notes area where you write notes and to have a separate maintenance process where you file them. OneNote also lets you link to notes internally, so you can have a dummy in one place and a link to the actual note in the dummy.
Although in the end I ended up with Microsoft OneNote (with Obsidian for special cases), Microsoft isn't going away and they don't have a habit of killing core products like Google does.