AirSane is a SANE frontend, and a scanner server that supports Apple's AirScan protocol. Scanners are detected automatically, and published through mDNS. Works with Apple's Image Capture, sane-airscan on Linux, and the eSCL client built into Windows 10 and 11.
A rough-and-ready package for OpenWrt is available at:
Works great for me, on a dedicated RPi Zero W running OpenWrt attached to my scanner.
Pull requests to AirSane-openwrt are welcome. It could, in particular, do with switching out the dependency on avahi with umdns.