(replying to myself lol)
I fixed it!!!
If anyone else is having this problem, it's most likely bc your graphics card doesn't like MKXP, or more specifically, OpenGL. Cass posted about this in the dev blog, but it was weird for me bc I have a geforce RTX 2060 which should be compatible-- but I found that in the graphics settings, the computer was running the game with the integrated graphics, which isn't compatible.
TLDR: Graphics settings in computer settings --> in "choose an app to set preference" pick "desktop app" and select the game.exe --> in "Options" set to your graphics card (probably listed as "high performance") instead of "let windows decide" or "Intel UHD Graphics"
Note: this is assuming your graphics card is compatible with all this-- if not, please look at Cass' post in the dev blog