@LoganFive
Do you need them to automatically sync across devices? If so, then do all the devices connect to the same LAN frequently? What operating systems do they run? Do you need to be able to collaborate with others? If so, then does it need to be in real time?
And what kind of features do you need in the notes themselves (e.g., bold text, tables, kanban board)?
I use Zettlr on PC and Markor on Android. I also sync my notes with SyncThing.
This link should help:
https://alternativeto.net/software/microsoft-onenote/