After update krenel to 5.8.12-3 unable detect touchpad synaptics and touchscreen wacom .
Is the 5.4 kernel detecting the devices?
5.7.19-2-MANJARO this kernel detecting the devices.
Kernel 5.4 detecting the devices .
I would stick with 5.4 for now. 5.7 is EOL = end of life, and test again when there is an update for 5.8 to see if things changed.
I understand, I will wait for an update or a new build