The Owlbear has played TTRPGs since the days of Moldvey Redboxes and Star Frontiers, but mostly digs on Path/Starfinder and indie games these days. Partner, puppy parent, gamer, veteran, and general nerd. LGBTQIA2S+ friendly. He/Him or Fae/Faer. Find Me Elsewhere
I dunno if you’re still lookin’, but there are a few options. I’m not sure why you bounced off of Obsidian (it’s what I use), but I’m gonna assume you need a more visual system. Obsidian’s Canvas provides that, but if you’re not using the other features, it’s a bit like swatting flies with a Buick.
The simplest option might be Gnome Notes. It’s very barebones, and probably not as freeform as you’d like, but if all you need is a simple note taking app where you can sorta Post-It stuff, it might be enough.
There aren’t a lot of options that work like One Note. Other folks have said Joplin, and that might be the closest. You could also look into:
That said, IIRC it is still possible to disable all AI stuff in the Notions settings. It’s something like Settings>NotionAI and then set all options to “off”. I dunno if that’ll stop Notion from suggesting you turn it back on, though.
Anyway, hope this helps.