External monitor uses full GPU memory

So the question is basically on screenshot

As many users of macbook pro 2019 16'' i have thermal issues and high Wattage (18W) for external monitor (DELL 2418D) Now I see that it continuously consume more and more GPU memory. I don't have any other dependencies except External monitor. Also I do just coding job, I have chrome, safari, firefox started and also Intelij IDEA, I have a lot of other tools started, but I wont to make a stress that nothing GPU related. My question is it expected and if not, what to do. Please do not respond with reset SMC, NVRAM/PRAM i did it 10+ times and it is not the fix, I have 10.15.5 Catalina installed.

Specs: 2.4 i9

GPU Radeon 5500 8GB

RAM 32

SSD 1TB

OS Catalina 10.15.5

Please just be honest and do not send me to contact apple support, it doesn't help a lot. Here I am more open to real fixes, not recommendations.