Legend, thanks for this!
I had exactly the same scenario and confirm that the "hacky" solution of editing the binary works perfectly (I used the Notepad++ extension to edit the 23.05.0 OpenWRT Factory image https://downloads.openwrt.org/releases/23.05.0/targets/ramips/mt7621/openwrt-23.05.0-ramips-mt7621-tplink_eap615-wall-v1-squashfs-sysupgrade.bin).
Thanks again,
Geoff