You need to check your dropped packet statistics to know for sure. iperf3 TCP over LAN will not see throughput affected by a few dropped packets, a stream 100ms

You need to check your dropped packet statistics to know for sure. iperf3 TCP over LAN will not see throughput affected by a few dropped packets, a stream 100ms away may take longer to recover. High bandwidth UDP testing with iperf3 should also expose this, the first measurement will usually see dropped packets.