There are some very hacky ways that involve special add-on cards for the motherboard, special motherboard model requirements, gpu connector requirements and eve

There are some very hacky ways that involve special add-on cards for the motherboard, special motherboard model requirements, gpu connector requirements and even special software to adjust the brightness. It is doable, but it is expensive, and it may or may not work properly. One example that I remember is one where some users who attempted the above setup reported that they need to unplug & re-plug the monitor after it sleeps.