Hello all!
I just fixed some performance issue related to RenderTexture size. All my RenderTextures was 4k and this was causing massive FPS drop on older computers. I adjusted RenderTexture sizes to screen space of each panel.
Also did some small code optimization.

I want to express my deepest gratitude to Frelude. He helped me to locate and fix this issue. Thank you again, Frelude! Please check his games!