They could be changing platforms from Android to iOS?
I would recommend checking out https://wiki.openstreetmap.org/wiki/StreetComplete#See_also for some alternatives.
Good luck!
SCEE is a fork of Street Complete with more features for advanced mappers. Available on F-Droid!
Links to the SCEE app:
F-droid: https://f-droid.org/packages/de.westnordost.streetcomplete.expert/
What features do you seek? There's Every Door that overlaps in editing certain features like building tags or some nodes like benches.Its's a lot more granular and allows for adding nodes. I think the two apps complement each other well.
No both apps are multilingual. If a language is missing it can be added since they are foss apps and in active development
similar Android Open Source Apps (from more similar to less similar):
https://mapcomplete.osm.be is a website where you can easily update and add new points to OSM. It is my favourite (because I'm also the one making it).
Instead of seeing everything at once, you get to choose many thematic maps, depending on what is interesting to you (e.g. 'shops', or 'restaurants', or 'cycling related stuff', or 'what is this street named after', ...)