Oh, sorry, I assumed I got it from F-Droid but unfortunately I got it via Play Store. 😞
There was an Android app out there where you could basically subscribe to GitHub releases and install their APKs, but I just noticed that the last Milktea release is from 2021 anyways: https://github.com/pantasystem/Milktea
Don't know if GitHub releases are still in sync with Play Store releases though.
Milktea seemed to work for me when I tried it when Firefish was still called calckey.social. kaiteki app just gave me a blank screen, so can't comment on that.