I can understand that. Maybe check the list I noted above, I’m pretty sure quite a few can do handwriting recognition (doesn’t the iPad’s native handwriting recognition work with Obsidian?). Though I understand the ‘don’t fix it if it ain’t broke’ inclination as well…

There are boatloads of various note-taking apps, both open-source and not, that are much better than OneNote. Take a look at https://noteapps.info/features, where you can browse by specific features you’re interested in. I’ve just recently switched from running DokuWiki for my homelab documentation to Joplin and I’m really loving it so far (I’ve setup sync to Hetzner’s S3 service).