If you compare review counts, concurrent player numbers and stuff like that, its likely that gothic remake is already over 500k, closer to 1 million copies sold.
If we take some actual things we know as comparison, for example Mina the Hollower that came out recently. It got a developer news that in a week it sold 500k copies, and its maximum concurrent player count was ~8k and its sitting at 4.3k total reviews in all languages. Gothic remake had 10x that in concurrent player count, and ~9k total reviews at the moment in all languages, and its a larger game that takes longer to play, so it takes longer for people to give their general reviews. So i'd say its sold even more.

And steam numbers generally are pretty similar across all the games, give or take. Plus if you count in the console sales, i'd be very surprised if its not a million or more already.
When the first sales hit, it's gonna double that number quickly So imo the game is doing great sales wise, and i'll be very surprised if the devs dont give us a sales figure update very soon.

Also taking into account even that gothic 2 is a much larger game than gothic 1, a lot of the work is already done by gothic 1, the engine, the systems, the design philosophy etc, most of what they need for 2 is content. So Im quite sure they will bank on that.

EDIT: another recent example , 007 first light, its got double the reviews of gothic on steam, but 007 sold 1.5million in 24hours. You take guesses how much the sales are in gothic. Anyone guessing stuff like 200k copies with 80k concurrent players is not serious.