In this session: Back to stock firmware it's better to add this information:
You can revert OpenWrt to version 19.07.10 and subsequently install the stock firmware using TFTP injection.
[OpenWrt Wiki] TP-Link Archer A7 v5
As mentioned in the forum:
TP-Link Archer A7 - Revert to Stock Firmware failed - Installing and Using OpenWrt - OpenWrt Forum