So … a few things.
Your drivers are already fine.
But what you didnt mention is that its a hybrid system.
You dont just have a radeon card … you have an intel iGPU and a radeon dGPU.
So first of all … you wont be using the radeon card unless you use DRI_PRIME=1
ex:
glxinfo | grep 'renderer string'
DRI_PRIME=1 glxinfo | grep 'renderer string'
Next … your dGPU card is legacy. So its using the old radeon driver.
But its just on the edge - as a Sea Islands card it can technically get ‘experimental’ AMDGPU support.
In order to do that you can follow this guide:
https://wiki.archlinux.org/index.php/AMDGPU#Specify_the_correct_module_order
(or you can optionally try just installing package amdgpu-experimental which should automate it)