Are there currently still PC games, similar to brain jogging, puzzle games (e.g. Crossword puzzles) or the like?

And where can you buy them? What are they called exactly? Something like an AppStore is also available for Windows laptops, right?

Yes, at Windows / Microsoft this is the Microsoft Store:

https://www.microsoft.com/...ps/windows

Sudoku and Mahjong are such games

Kenken: http://www.kenkenpuzzle.com/#

2048: https://play2048.co/

Dr. Kawashima is still there!

Of course.

If you just want to do some brain jogging, take a sudoku. There are now even the strangest versions where you just think: "Is that still Sudoku at all?!"

Maybe something like that here?

http://www.purplehills.de