You're on the right track.
This is exactly what the p30 pro does when the bottom mic stops working.
The mic is soldered on a small pcb that has the simtray on it.
Do inspect your part before installing it because I’ve seen alot of them being very badly refurbished for resale where the IC and stucked there with glue instead of being soldered to the board. It might be hard to see without a microscope, but I just want to let you know that that is a common practice with the P30 pro sim/mic board for some reason.
I hope this helps.