Coding diary for the interested + some Windows10 facts:

• I wanted to use pygame, but it natively doesn't allow multiple windows plus doesn't allow UTF-8 characters in captions
• I tried cocos too but it is overcomplicated for the task TBH
• pyglet could run multiple windows and render UTF-8 in title bar, but it (or underlying opengl) has a bug (or rather a feature?) that removes the new windows above 12 of them (I needed 36). So I tried running the windows in different processes with multiprocessing module and multiprocessing's build IPC, and it has finally worked. Though shit likes to consume the CPU.
• default Windows 10 (Segoe UI) font isn't monospaced but I could emulate it using different width UTF-8 space characters
• about 320 characters seems to be rendering limit for Windows titlebars (because of this bug, the whole thing took me 3x more time than it should have)