It still amazes me when people say the Steam charts numbers are the playerbase. That’s not how the Steam charts work.
All they show are the current number of logged in players, the past daily peak numbers, and the highest daily peaks of the past months.
The charts do not show how many accounts in total played the game during any given day, nor do they have any way of showing how many accounts in total play the game during every week and month.
There are people who do not play every day. These people also play the game on different days of the week. We also live on a planet with time zones and no one plays the game 24/7. Every day people play the game at different hours.
Let me use a very simple example if this is hard to understand. Game X has a peak of 10 players one day. Five people played the game for an hour that day, then logged out. Then five other people log in and play it for an hour and log out. Then five more other people log in and play the game and log out. Then ten people log in, play the game and log out,
The current number of players would go from 0 to 5 and back during the day, then to 10. The chart shows the daily peak was 10 players. Is the playerbase 10 players or is the playerbase the total amount of players who played the game that day? Again, charts will only show 10 players as the peak.
This is why games which have peaks of hundreds of thousands on Steam are actually played by millions of people. Only the devs & publisher have true data about the total number of active accounts. That is why when the game launched and got to slightly over million player peak in Steam, it was reported that there were about ten million active accounts playing the Steam version(Korean version has a similar amount of players too).
Of course we now know that there have been at least several million bot accounts too, so the true playerbase of the Steam version has not been ten million at any point. But it has been in the millions, and a daily peak of 600k indicates it is still several millions despite there being plenty of bots as we all know.
There are games with daily peaks around 600-1000 on Steam charts which have been recorded having actually 30-50k active accounts per month. This sort of a thing gives you some math which to use as a multiplicator when estimating true size of the playerbase.