It doesn't work for everyone, but I've enjoyed using #anki in the past. It seems #AnkiWeb has some user-contributed #Gaelic lessons: https://ankiweb.net/shared/info/1357645930

On Android, I use #AnkiDroid from #FDroid

I use the Aurora Store, a FOSS interface to the Play Store. You can either get it through #fdroid, or download the apk directly from the Aurora Store site. It's also Step 12 in this guide, which I found useful when I was getting started with #grapheneOS https://redandblack.io/blog/2020/how-to-set-up-grapheneos/

Just installed #grapheneOS on a Pixel.

No #fdroid?

Head to the forum, and most people are recommending google play inside the app sandbox. In there I found and read this long article detailing F-droid issues by @wonderfall (thanks!)

Interested to hear from other Graphene users how they are doing apps and why.