WDS throughput limitations

Hello all,
we need to connect wireless clients using WDS because we need to bridge PPPoE protocol from behind client’s wireless bridges (there are more PPPoE clients connected to ethernet port of the Mikrotik that is connected through wlan1 to AP).

But we know, that using WDS, throughput of links created using more WDS APs is exponentially decreasing because all traffic is repeated to each member of WDS.

Is it the same with station-wds clients? Is there a way we can connect more WDS clients without replication of the traffic to each-other?

Moreover, WDS created over wlan on AP must be in bridge with ethernet port (that connects AP to WAN network). Does it affect the throughput problem?