And here I thought my Google-fu was good… shakes head
Welp, it’s in the AUR:
$ pamac search 8852
rtw89-dkms-git 1:r148.4dc5371-3 AUR
Driver for Realtek 8852AE, an 802.11ax device
So can be installed using
pamac build rtw89-dkms-git
But make sure the headers for your kernel(s) are installed first:
pamac install $(pamac list --quiet --installed | grep "^linux[0-9]*[-rt]*$" | awk '{print $1"-headers"}' ORS=' ')
This will install the kernel headers for all installed kernels.
Note:
I just remembered why I didn’t recommend it: it’s because it mentioned it was for the Realtek 8852AE, while yours is, in fact, the Realtek 8852BU from what I was able to see.
I also noticed you tried that already, so this will probably not work.