A different ethernet phy would be reason enough to get console access before trying anything else. It may be as simple as ensuring the right driver is included in the image for the RTL8211, since the devicetree doesn't specify which phy is used exactly, but you'll have to find out yourself.
The 5GHz radio, LED GPIOs, and button GPIO all appear to be identical.
It looks like they also changed the phy on the EAP225v4, so maybe they're having issues sourcing the AR8033 that was used originally.
Edit:
The devicetree definitions and packages in OpenWrt were already (nearly) identical, and it looks like TP-Link has also switched to a unified firmware for the EAP225 v3/v3.20/v4 and EAP225-Outdoor v1/v3:
SupportList:
EAP225-Outdoor(TP-Link|UN|AC1200-D):1.0
EAP225(TP-Link|UN|AC1350-D):3.0
EAP225(TP-Link|UN|AC1350-D):3.20
EAP225-Outdoor(TP-Link|UN|AC1200-D):3.0
EAP225(TP-Link|UN|AC1350-D):4.0