Hello Eric sounds like a cpu usage issue
What is the bit rate and buffer size you are using on your pc? You need the Motu M2 driver to see that.
Since you cannot configure that on the phone motu might be trying to use what was set on the PC. If the PC is high (like 96K bps and 512kb) you can try to reduce them. Since your phone’s processor might not be handling it well.
I suggest 48K bps rate and 256kb buffering.
Also can you please try the extreme audio app (the mobile daw that I suggested)
That static bass sound happened to me in an older PC when I was using voice meter banana on 4 channels and recording a video on obs…