I've found that other people with RX 5600 XT had problems with this version of mesa.
https://bugs.archlinux.org/task/70554
https://gitlab.freedesktop.org/mesa/mesa/-/issues/4691
There is a new release of mesa (21.0.3-2) that fixes the problem for those users.
Hope that you upload it to focal-proposed.
I've found that other people with RX 5600 XT had problems with this version of mesa.
https:/ /bugs.archlinux .org/task/ 70554
https:/ /gitlab. freedesktop. org/mesa/ mesa/-/ issues/ 4691
There is a new release of mesa (21.0.3-2) that fixes the problem for those users.
Hope that you upload it to focal-proposed.