How can I enable TSX on my Mac? The furthest I got was by trying to add a kext that would enable me to r/w to the model-specific register but I can't install non signed kexts on my Mac. Any alternatives?
Anything involving accessing low level features like CPU instructions is going to require kernel access. This is definitely a case of you should know what you're doing first, as messing with memory on the kernel level seems like it would have any number of terrible ways it could go wrong.
Assuming you do, you can install unsigned kexts by disabling the System Integrity Protection.
To do so, boot into recovery mode (hold ⌘R when rebooting), open Terminal (in the Utilities menu), and run
csrutil disable. Then reboot as per usual and install the kext.