The repository is at https://github.com/lwfinger/rtw8852be and has detailed instructions to compile and install.
I followed the instructions and have WiFi working again on kernel 6.1.43-vendor-rk35xx
The only difficulty was to find the correct headers package: linux-headers-vendor-rk35xx
My OPi5Plus has the additional WiFi PCIe card, which was visible with the previous vendor kernel version, 5.10.160-legacy-rk35xx or package linux-headers-legacy-rk35xx.
Though managing both cards used to be buggy, I only see one card now. Not perfect but enough for my current needs.
bolet75 got a reaction from Boonleng Cheong in Hope to get rtl8852be wifi driver support for kernel 6.1