I have no solution for you, but the strange texts are the window plates of other users. Perhaps you can try to remove your own window plates and see if that changes anything.
Also, when you configured OBS, did you use the window capture mode? And if so, did you use the window from singleplayer or multiplayer? The window names are different, but if you use singeplayer to set up OBS, it'll also work in multiplayer. I don't know if it's vice versa. Try setting up OBS again using window capture mode and singleplayer. You could also try to change the rendering mode to OpenGL if you're using DX