Since RedPill is built using OpenGL, and OpenGL is deprecated, RedPill will probably stop working for good eventually.
In the mean time, here's a quick attempt to update the project and build RedPill for 64 bit, so it will run on macOS 10.15 and up. I've also attempted to build it as a fat binary to support M1 Macs.
I don't have a $99 Apple-approved signing key to sign it with, so you'll need to do the usual dance to run an unsigned binary, or sign it with the codesign utility:
codesign --force -s - RedPill.saver/Contents/MacOS/RedPill
The binary works on my Intel MacBook Pro (2020). I don't have an M1 Mac to test with.