Small correction; it’s DisplayLink, not DisplayPort. You have to use DisplayLink because they do some part in software as a part of their driver (which you must download and install) whereas the native Apple stuff has some internal hardware limitation.
I run three 1080p monitors off of my M1Pro, and I don’t notice any heavy CPU load from whatever software load the driver may be adding.
I run three 1080p monitors off of my M1Pro, and I don’t notice any heavy CPU load from whatever software load the driver may be adding.