Write is a handwriting app that works on a lot of platforms including Linux which cannot be said about most handwritten note-taking applications.
More information and demo: https://github.com/styluslabs/Write/
I’ve used it for uni on a Linux tablet/convertible and it worked really quite well and has some nice convenient features for note-taking.
The UI looks like it’s from android 4.something though ^^’
What I really appreciate about it is that its storage format are plain SVG(Z) which are extremely compatible. All you need to view your scribbles is an SVG viewer (i.e. a web browser) which basically every computer with a GUI has. Their website is in fact mostly just the output of their own app.
To be fair, we have it quite good in this regard between Xournalpp and Rnote. Certainly areas where we only have worse options.