I am surprised that no one has mentioned Rnote yet.
It is my favourite newly-created program for Linux. It is a relatively new app which supports annotating files and taking handwritten notes. You can import PDFs, set the page size to infinite or a fixed size (something OneNote can't do), adjust the background to display grids or lines or dots or nothing with any spacing you like, input text with your keyboard, .... It is available on Flathub for easy installation.
The only major downside is the following: Disclaimer: The file format is still unstable. It might change and break compatibility between versions.
Oh no, I thought that was a feature. I came to rely on it to transcribe long tab titles into my text editor. Is there any way to restore the old behaviour in Firefox? Otherwise I'll have to stick with Firefox 118 or switch web browsers, since Firefox 119 seems to break my longstanding workflow. :(
Any ideas?