But then you don't have smooth scrolling.

Enabling apz kinetic scrolling is another approach. That cuts the lag by about 90%, getting it much closer to chrome.

Exactly. This is what fixed this issue for me as well. What I haven't been able to fix is that new windows open rather slowly.

I'm so used to scrolling by keypress (i.e. any of the vim-like extensions), with smooth scrolling disabled and a higher scroll step, that I just recently noticed that this reduces resource usage/heat.