i carry an iphone 12 mini and being so small it had the tendency to slide around while placed on the charging mat in my Hyundai i10 MK3 so i replaced the rubber mat with a thin and flat surface that allowed me to stick an adhesive magsafe magnetic ring underneath it.
This is the magnetic ring that i used: https://amzn.eu/d/7Sr8bR8
You can source one from your favourite retailer but it is very important that the ring itself must be made of magnets. I tried the simple metallic ones and they don't work.

You can secure the mat to the ring with doubleside tape or you can leave it like this, the fit is quite precise and it will not move around causing noise. i strongly recommend to print it in PETG on a very clean build plate otherwise you may see some streaks of old pla onto the surface of the print and wait for the plate to FULLY COOL DOWN before peeling off the print to avoid warping or damages to the build plate.