USB C to C (non thunderbolt) screen knows something is plugged in but macOS doesn't detect it. Same issue on both my M1 mini and M1 MacBook Pro 2021. USB C to HDMI is detected but is distorted with signal cutting in and out and a high pitched noise from the monitors speakers.How are your external screens connected? USB-C(actually thunderbolt) to the thunderbolt port on the screens?
Because that works for me without a problem.