Unfortunately my personal search for the same has left me with 2 conclusions:

• Android is terrible for this. Most ergonomic way is to use Orgro or something as read only, and if read-only is not an option, then use an the full Emacs port for android (available on f-droid) which cones with its own input-related challenges.

• Ultimately what is going to work is getting something like GPD Micro, a small machine with dedicated keyboard. Anything short of that is going to fail one way or another.

I am in a similar boat. I decided to write my own app (learning android development so it's going slow).

I was using orgzly earlier but it doesn't fit in with org roam workflows.

Also check out logseq and its mobile app. I have heard you can make it work since it can use org mode files as the backend.

update for later generations: https://org-roam.discourse.group/t/import-of-obsidian-notes/609/3

it seems to be easy and seamless to use org-roam with md-roam, and use obsidian on mobile and emacs on your real computer. I might update this post with more details once I tried it.