High GPU memory utilisation with external monitor

I am seeing the GPU memory increase to a high figure on iStat Menus there is a discussion on this here:

https://apple.stackexchange.com/questions/374506/can-i-flush-or-release-my-gpu-memory

Is there an elegant solution for this other than disconnecting the external monitor or using hot corners set to turn the display off? I used to disconnect the HDMI cable, but now turn off displays using hot corners.

Thanks.