The next version of batocera (32) has an option in the GUI for enabling the MicroVU speed hacks, particularly MTVU which is highly recommended by the PCSX2 devs and in my testing gave ~20 FPS increase in demanding titles like GoW II.
The MTVU option was previously disabled and required using the F1 escape to configure PCSX2 manually. But one thing the change in 32 does also is if MicroVU speed hacks is set to auto it will automatically apply the best speed hacks based on your CPU; which means you don’t really need to even configure it.
So wait for version 32 or maybe check out the beta and see if that makes things better. Otherwise you can still add this hack in 31 but as others have mentioned you need to do it manually.