Hi @Rhaom ,
I suggest you to read first this post in order to solve your problem.
‘Qualcomm Atheros Troubleshooting Guide|20201019’
Otherwise, there are a couple of post related to your comments.
https://forum.manjaro.org/t/internet-connection-gets-very-slow-stops-completely/33103´
In this post read the Hook to fix the Artheros QCA937 firmware issue, although is older.
´https://forum.manjaro.org/t/creating-useful-pacman-hooks/55020´
Hope it help, regards,