I actually just realized I didn't have my secondary drive (an HDD) plugged into the SATA plug when I booted it up. This doesn't make sense to me (maybe it will for you), but when I plugged it in it actually reactivated my M.2 (brand BPX nvme).
So basically if you run into an issue similar to this make sure you have the same configurations as before you changed power supplies and see if that works, it worked for me.