Hello, what could lead to such a vast difference in throughput and bandwidth?
I configured the dap x1860 as repeater using relayd, running snapshot build from 2023-01-07
There is low competition for wifi channels.
Whole network (apart from far distance noise):
Client Intel AX200 on Windows 10 (192.168.178.33) < --- 2 Walls (~5 meter) --- > D-Link DAP x1860 < --- wifi "Buero" --- > Fritzbox 7490 OEM
What I see is that sometimes i get full 80MHz on both streams, but more often than not, it drops on the RX. For example, when connect with a client, it's like flipping a coin to get full 80MHz, or lower one on RX. Then when connected, having another client connect, will lead to drop in bandwidth on RX, (unless what i saw was a coincidence). Disconnecting the other client will NOT immediatelly again lead to increased bandwidth 
Edit:
RX = received data from a link
TX = transmitted data from a link
Anyway, since RX is "received" data, the first bottleneck to look at would by my Intel AX200, but since there is some negotiation going on, i thought maybe my D-Link-dap-x1860 will have an influence too?
Here a screenshot with better result:
I have seen 650 Mbit/s on RX too without having changed ANYTHING in my configuration, or having clients connect or disconnect. The only discerning factor I can isolate is "time".