Returned to play after looking at the news about the latest patch. Apparently, the achievements are working now.
Good news for Steam Deck players: your achievements progress actually works in offline mode!
Update: (04/22)
Sadly, your achievements progress can't carry over between desktop and Steam Deck. For instance, if you have 5,000 enemy destroyed and you move to Steam Deck, it goes to 0 due to the game thinks you're playing on different system.