Hi,
I just bought an TL-WR902AC V3 and tried to install OpenWrt as described.
But the installation always failed.
The device had a rather new Firmware version installed (TL-WR902AC(EU)_V3_0.9.1 Build 220329)
Installing an older version (TL-WR902AC(EU)_V3_191018) did resolve the problem
and I could install OpenWrt (22.03.0) as described.
HTH
Ralf