First, thank you for what seems to be a great distro. I am very new to Manjaro and RPi but a long time Linux user on x86_64.
Using the 20.08 release, Xorg is horribly slow. glxinfo does show hardware acceleration, but it is very laggy, including keyboard and mouse use. There does not appear to be anything running in the background which would cause this. Using glxgears, I see around 20 fps on a 4k monitor, just horrible.
If I boot with Ubuntu 20.04 LTS, I see 200+ fps and all is good. I will dig deeper and find the cause but thought I would post here to see if others experiencing this issue?