Hey there!
You clearly didn't try searching. That's already been discussed. The thread is named "Vlan trunk over wlan". If I search for your exact thread name, the first result is this very thread, the second result is the one I'm referring to.
https://forum.openwrt.org/search?q=vlan%20trunk%20over%20wireless%20link
Here it the thread, especially my comment on it.
I don't get it. We already discussed it in detail.
I used gretap through any trusted IP connection. No matter if its WDS, wifi client, any VPN you like or powerlan. As long as you use gretap to tunnel through any IP connection, there's nearly no overhead to the tunnel itself ans you can easily use that gretap tunnel as vlan trunk assigning e.g. @trunk.100 for vlan 100.
See:
https://forum.openwrt.org/viewtopic.php?id=71080
I even provided you with a working example that I confirmed to be …
See the linked threads in both, lede forum and openwrt forum as well as the config I provided.
Regards,