Batman-adv over two Radios


i searched for quite a long time but i think my question was never answered before, i couldnt find anything related to it, or i am just not smart enough to understand :smiley:

So, what i am trying to do is setting up a wireless Repeater using 802.11s or WDS, but because i want fast (and) reliable Wi-Fi, i tried connecting two 5GHz radios with each other.
I am using two Fritz!Repeater 3000, they have two 5GHz radios and one 2.4Ghz Radio, but the "Gateway" Fritz!Repeater 3000 for the Wireless Repeater is connected via Ethernet to the main Router, therefore this is not a complete wireless Mesh/Setup.. i tried using Batman-adv for this, but the wireless Repeater couldnt get an IP Address, and i could not access the Interface.. when i just tried connecting them, without assigning a network,it ofc worked. I just dont know, how to configure Batman-Adv correctly for this use case. I think what i am trying to do is called "Dual-Band Repeating" or "Cross-band repeating".
(One 5Ghz Radio is forced to use DFS, but is faster, and the other one is slower, but doesnt need to use DFS, thats the reason why i want to use both)

Is there anyone who maybe has a similar configuration or any tips?

And, another question is, do i need batman-adv only on the nodes that are wirelessly connected, so the Wireless Repeater and the Fritz Repeater 3000 (Gateway to wired LAN) or would i need to install Batman-adv on every OpenWRT Device?

Best regards!