On modern versions of Android, it's possible to load alternative Vulkan drivers for certain Adreno GPUs using something called libadrenotools. These can sometimes perform better and with less bugs than the drivers shipped with the device.
This is supported from PPSSPP 1.17 and forward.
Note that if your GPU isn't one of the supported GPUs, this option will simply not be visible.
This feature is not nearly as beneficial as it is for say Dolphin, Yuzu or RPCS3 since PPSSPP intentionally uses quite a minimal GPU feature set, but it can still be interesting to experiment with to get the best performance out of your device. Don't expect miracles though.
Note that this feature is not available for phones with ARM (Mali) or PowerVR GPUs, nor any other type of GPU other than modern Adreno in. You can check what GPU
you have by going to Settings/Tools/System Information within PPSSPP.
Also note that these drivers only apply to Vulkan, not OpenGL. OpenGL always uses the pre-installed proprietary driver.
Go to the AdrenoTools driver release page and download drivers to your device from, and keep them as ZIP files in your downloads directory (do not decompress).
Then, in PPSSPP, go to Settings/Tools/Developer Tools, and choose "AdrenoTools Driver Manager" (if you can't find it, this functionality is not available for your device, sorry, see above). On the screen that pops up, choose "Install custom driver" and pick the ZIP file out of Downloads.
After that, your new driver will be selectable below. Just press the Select button next to the name of the driver.
You can also remove drivers by clicking the garbage can. This button will not be visible on the currently selected driver.
To restore you regular graphics driver, just select the "Default GPU Driver".
Mesa is the Linux project that maintains most open-source GPU drivers. Turnip is the Adreno Vulkan driver in this suite of drivers.
It supports more features and extensions than the official driver. Performance varies but is often somewhat faster.
These are official, proprietary drivers from Qualcomm, the company making Adreno GPUs. Sometimes bugs can be worked around by picking a different version of this driver. Note that many of these can have problems on certain devices, and I generally do not recommend using these unless they specifically say that they're suitable for your device.