Among Us has seen its concurrent player count drop to 24 thousand on Steam.
Source: Steam Charts
This is down from 176 thousand people in October 2020. The metric began to decline dramatically in November 2020. This is mostly due to the absence of new content for the game, as well as the arrival of other popular games like Valheim.
To be fair, this is only relevant for the Steam version of the game, whose playerbase, according to some reports, is only 10% of the total spread across iOS and Android.