There are multiple threads active right now with similar issues as you guys.
Seems to be kernel related.
Some report it works on linux61, some have to use linux515.
You could try to install drivers from AUR, but I would say it’s better to use a different kernel until the issue is fixed.
Edit
I just saw this, might be related.
And
Try to sync and update. Make sure your mirrors are up to date before running update by confirming with pacman-mirrors.
If at least one mirror is [OK] run sudo pacman -Syu