They need to work on moving everything over fully to DX11, Or even Vulkan, As they are still mainly on DX9 and the performance sometimes ingame shows this with very low GPU usage in many areas as well as crappy AA, I think Vulkan would be better in the long term as CPU usage is a bit hit'n'miss in ETS2.
It's pretty annoying especially when you have a few graphical mods in place and you see your GPU usage hover around 30-40% even at 3440x1440, The whole game engine needs an overhaul.