[2023] Steam voice chat possible while in-game?

Yes, you can. Alternatively, you could use third-party software like Discord or Teamspeak to chat with your friends while playing.

No clue how that works on Steam, you're better of using Discord or Teamspeak anyhow. Such general Steam related questions can better be asked in the official Steam forums, btw. As it is rather off-topic in game hubs.