I've been using overlays for OrangePi-zero and OrangePi-R1 for over three years.
There was also a message on the forum.
The boot-config package is here.
Overlays are added after the images are assembled on the SBC itself.
An example of installing boot-config and enabling Wi-Fi (xradio-xr819) for Orangepi-Zero (OpenWrt 22.03.6 stable firmware image for MMC).