I know I’m late to the party but I just found out and didn’t find a post regarding this
TL;DR: Steam now calculates review scores based on reviews made on your languages only (if enough). This is on by default, but can be reverted to go back to review scores based on all reviews (from people that purchased the game directly on Steam only)
I would argue against this. I have seen more diverse rating, but 1 to 5 still isn’t really accurate
GOG also has a massive problem: you can’t edit your review once you published it