MacBook Pro Mid 2015 Display flickering to static/weird colour during usage
This is a hardware issue; most likely a failed GPU.

I wrote an answer addressing this same issue but diagnosing by booting a Linux is not so easy anymore.

You can attempt to run Apple Diagnostics by booting and holding D.  It may or may not return an error code.

However, virtually every time I’ve seen something like this, it required a logic board replacement.