Do you think you can learn highschool stuff via games?

It can be useful as an example of educating, like in Assassin's creed series teaching History somewhat.

think it depends on the game, assassins creed for example yes it's very historical, but not all of it is true obviously as its ramped up too make the game more entertaining.

Yes, I know a lot of courses on YouTube through games, for example, an explanation of higher mathematics through minecraft, etc.

Honestly, gaming is not a reliable source of information. The programmers of a game are not experts on the material provided and games are usually used as an escape from reality which makes it hard to bring reality into the game. However, I do believe that you can learn out of the box thinking from gaming. Strategic games and such provide brain work that enables you to think more in depth and out of the box than just your normal everyday assignment.

I learned english with the help of games and movies. I live in Ukraine, we have very different language (something like russian)

I've learned a foreign language through games, and I can easily find educational games for a toddler. It depends on the type of game you're playing, but in most cases not really.

I dont think you can. Games are based on historic events but you cant really study it.

Yes, you can. For example, there is a minecraft server where they teach different languages, for example, English, a zoo is built on the map, or something else, children and a teacher enter there, and show and tell everything. So with each game you can learn something new for yourself.

not really to be honest kekw

Depends on what you're trying to learn. Civilization won't teach you history, but is great for thinking about anthropology, how culture and science develop, and showing how complex systems interact (in a far more interesting way than most text books would). Math is in every RPG. Tycoon games are business management. Most of this sounds more like college courses though.