Wifi client mode - LAN IP in same subnet

Installing and Using OpenWrt Network and Wireless Configuration
1

Hey there,
I am new to OpenWRT, LEDE and this forum, so my question might seem a bit weird to you but I simply cannot understand why my configuration won't work for me. I've connected my LEDE-device to my existing wifi network using client mode, this works fine. I can access the LEDE through my wifi network without problems. But now I want the LAN ports of the LEDE to be on the same subnet as my main router, so the DHCP server of my main router can give the addresses to the devices connected via LAN to my LEDE. However, I can't find a way to do that.
I've seen this concept working with normal TP-Link routers which are set to work in client-mode.
I hope you understand my question, if not feel free to ask for clarification.

Thanks for helping in advance

2

https://openwrt.org/docs/guide-user/network/wifi/relay_configuration

3

You have to enable wds (4 address mode) on both wifi ap and client.
Probably your main ap does not support this specific operation mode.

The issue you are encountering is because you need to transfer 4 mac adresses (source, destination, source wifi and destination wifi -mac) over your 802.11 link and without 4 adress mode you have only three.