Heres my tier list of open source android apps, I have only included ones i feel I have used enouph to understand.
Please tell me any of your favorite open source apps as I would love to hear.
S tier- OpenCalc, firefox, thunder, organic maps, Aegis authenticator, wikipedia, translate you, F-Droid.
A tier: open camera, fossify suite, k-9, termux, simplenote, Acode, pie launcher,
B tier: gallery (by iacoblonut), peer tube, simple keyboard, floris board (might be higher if it used haptic feedback interface by default), unexpected keyboard (would be S tier if shift did not carry on selecting text once released).
C tier: FreeDcam, libre camera, geo notes, free paint.
I hear you. I have spent a while going down the rabbit hole for note apps.
If you want better markdown with sync capabilities, you may be interested in Joplin. It’s very similar to that one app. Though it’s not completely effortless, it is fairly simple. It’s a fairly quick read, too: https://joplinapp.org/help/apps/sync/
Speaking of that app, if you’re interested, there are community plugins through that app that let you sync through cloud services, which would allow you to cut out the Simplenote middleman. Just search for sync in the plugins and it should be the first one. From what I’ve read of Nextcloud, it’s open source and you get 2gb free for a single account.