SOLVED FOR ME:
My Setup:
Fibre to home into a ZTE supplied router from my ISP.
ZTE wifi disabled.
ZTE ethernet connect to TP-LINK mesh network.
Mesh 2.4 and 5 GHZ run same SSID and Password
How I installed: (This game me the same problem)
Connected Homebase 2 to my ZTE router with ethernet, cause it is the closest.
Activated the 2.4ghz on the ZTE - this has the same SSID and Password as my Mesh.
Deactivated Mesh wife to ensure my phone and Homebase are on same network.
Added HomeBase and 2C pro cams succesfuly to HomeKit.
Can view cams in both Eufy app and HomeKit.
Switch off ZTE Wifi and activate mesh.
All connected well, but could only view cams in Eufy app and not HomeKit..showed off line.
Took me hours of trouble shooting and resetting, reloading.
Then finally, I connected my HomeBase 2 directly via ethernet cable to a mesh unit.
And finally cams showed back up in HomeKit.
Not sure why, but seem like the HomeBase wants to be connected via Ethernet to the Router sending the Wifi SSID. Even thought the SSID and Password was exactly the same. Them moment I had my Homebase connected to the ZTE router and phone to Mesh Wifi. HomeKit would not show the feed.
Hope that makes sense.