I'll interpret non-US a bit broader as non-English. English is hugely dominant in scifi so it's often hard to find good books in other languages. I'd also love to hear the recommendations of others too! A few I read:

• (German)
  • "Die Welten der Skiir" trilogy (by Dirk van den Boom): https://bookwyrm.social/book/593373/s/die-welten-der-skiir-1 is really great . He also wrote another trilogy (Die Reise der Scythe) which is also quite nice.
  • "3517 Anno Domini: Wir waren Götter" by Raik Thorstad. Note that his is a primarily an M/M romance, but it has a nice dystopian scifi setting.
• (Spanish)
  • "En un lugar llamado tierra" - I read this long ago, don't remember much: https://bookwyrm.social/book/979935/s/en-un-lugar-llamado-tierra
  • La señal - https://bookwyrm.social/book/979918/s/la-senal
• (French) The works by Jules Verne should probably be mentioned here, despite being written well a century ago. "Vingt mille lieues sous les mers", as already mentioned in another comment, is a must-read classic.
  • "Helstrid" - I have this one on my e-reader for a while but haven't properly started it yet: https://bookwyrm.social/book/1289177/s/helstrid , so I can't say if it's any good.
• (Dutch) Long ago as a teen I once read "Coriolis, de stormplaneet" and liked it: https://bookwyrm.social/book/979934/s/coriolis-de-stormplaneet