So I have some good news and bad news. Good news is I have since upgraded my CPU from the i7-6700 to an i5-12600K and now the frame rate issues are fixed. Even on ultra settings at 2560*1440 it didn't drop below 60 FPS. The bad news is that now if I set the graphics above "Low" the screen flickers constantly.
Intel i5-12600K | 16GB DDR4-3000 CL15 | XFX RX 590 8GB Fat Boy | Mesa 23.1.7 | WD SN850 500GB | Solus | Mate 1.27.0 | Kernel 6.4.15-254 | MSI G2730QPF 2560*1440 @ 165hz