Jerboa and Eternity are native Android apps (the first uses modern technologies like Kotlin and Jetpack Compose, the second one has a lot of Java code and the UI is made with XML layouts for activities/fragments);
Voyager is portable web app built with React in Typescript, with mobile flavours made using Ionic capacitor;
Thunder is a cross-platform app built with Flutter in Dart (like Liftoff and Lemmur were in their days);
there are other FOSS apps like Combustibile (native/Java+XML) or Muffed (Flutter)...
I was using Eternity, then switched to Summit but after learning that the GitHub repo was only to let people use obtainium (so no real source is available), switched back to Jerboa. Now that it has support for moderation tools, I don't think I need to make a switch atm.
I also tried and liked it, though I switched back to Jerboa because I would always support the development of an open source app over a closed source app. The summit dev also said that he won't open source it so I never will use it again.