I would like to use my laptop for note taking in class, and use an android based e-ink tablet for handwriting and diagrams. What are your recommendations for delivering the tablet's notes to the vault?
Obsidian on the tablet with first party sync looks like a possibility. What about another app that can use SyncThing or similar that the laptop vault can turn pull?
I use git to synchronise and versionise my notes across my desktop pc and laptop. If I need access to the notes away from those two I simply access my git repository I self-hosted via gitea. Sure it has not the linking features of obsidian, but I still can read and edit the markdown files :)
My use case by the way is world building for a literature project and running Pathfinder Role-playing games.
I do the same thing, using a home-grown Git sync solution to keep my vault synced between my desktop, laptop, and Android phone. Free, and easy to setup on the computers, needed some additional SW on the Android side to get the sync to work.
I use Dropbox to sync between my tablet, phone, and laptop. Dropbox let's you use three devices for free so I don't pay anything for this solution and everything is backed up to Dropbox. My phone and tablet are both android devices so I use dropsync to actually do the syncing with Dropbox so that they can be accessed via Obsidian.
Their basic (free) plan only allows you to be signed in to 3 devices at a time. So, for example, if I were signed in on my home computer, work computer, and phone (via the Dropbox app), I wouldn't be able to sign in on my tablet (via the app). I specify the app because I think you could still sign in via the browser and download files, but you wouldn't be able to automatically sync files to the tablet.
The Dropbox docs say the basic account only gets 2GB, but when I look at my account it's showing 3.2GB with 65% so I'm not sure what the actual number is. They kind of bury info about the free tier but you can visit the link below.
You can read this article. https://lemmy.ml/post/4161707. Syncthing is free, open source, simple to set up, and much faster than a repository based solution. The article explains why and how to set it up.