Hi,
as far as I can tell, you are trying to install an improper driver. If you have a WiFi device with rtl8812bu chipset (to be determined with inxi -Fazy, as j8a already mentioned), the following driver from the AUR will work : rtl88x2bu-dkms-git by RinCat.
Don’t forget to install the appropriate kernel headers. For kernel 5.12 you can do this e.g. via the terminal with the command sudo pacman -S linux512-headers.
Then you can then install the PKGBUILD rtl88x2bu-dkms-git via Pamac, either using the GUI or the terminal. After that, restart the computer. In Pamac you have to make sure first, that AUR support is enabled in the preferences.
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