I used a TR6 (Torx security with the hollowed tip, as per the ifixit instructions) on both the “red” and “yellow screws”, Mini 2020 model.

Also, the red ones had a small amount of blue stuff (thread compound?) around the threads, which made it slightly trickier to reinsert them straight. No big problem though

Successfully followed this guide with an upgrade from 8GB (2x4) to 16GB (1x16) on the updated Mini 2020 model.

Thanks ifixit.