Der RPi4 kann 2,4G und 5G funken. Dann testen wir mal. Als Gegenstelle nehme ich mal meinen ROCKPro64 
pi@raspberrypi:~ $ iperf3 -c 192.168.178.27
Connecting to host 192.168.178.27, port 5201
[ 5] local 192.168.178.40 port 45642 connected to 192.168.178.27 port 5201
[ ID] Interval Transfer Bitrate Retr Cwnd
[ 5] 0.00-1.00 sec 11.0 MBytes 92.0 Mbits/sec 0 553 KBytes
[ 5] 1.00-2.00 sec 11.6 MBytes 97.0 Mbits/sec 0 899 KBytes
[ 5] 2.00-3.00 sec 11.6 MBytes 97.1 Mbits/sec 0 1.30 MBytes
[ 5] 3.00-4.00 sec 10.0 MBytes 83.9 Mbits/sec 43 1.17 MBytes
[ 5] 4.00-5.00 sec 12.5 MBytes 105 Mbits/sec 0 1.30 MBytes
[ 5] 5.00-6.00 sec 10.0 MBytes 83.9 Mbits/sec 0 1.41 MBytes
[ 5] 6.00-7.00 sec 11.2 MBytes 94.4 Mbits/sec 0 1.50 MBytes
[ 5] 7.00-8.00 sec 10.0 MBytes 83.9 Mbits/sec 6 1.08 MBytes
[ 5] 8.00-9.00 sec 11.2 MBytes 94.4 Mbits/sec 0 1.16 MBytes
[ 5] 9.00-10.00 sec 11.2 MBytes 94.4 Mbits/sec 0 1.22 MBytes
- - - - - - - - - - - - - - - - - - - - - - - - -
[ ID] Interval Transfer Bitrate Retr
[ 5] 0.00-10.00 sec 110 MBytes 92.6 Mbits/sec 49 sender
[ 5] 0.00-10.00 sec 108 MBytes 90.5 Mbits/sec receiver
iperf Done.
pi@raspberrypi:~ $ iperf3 -R -c 192.168.178.27
Connecting to host 192.168.178.27, port 5201
Reverse mode, remote host 192.168.178.27 is sending
[ 5] local 192.168.178.40 port 45646 connected to 192.168.178.27 port 5201
[ ID] Interval Transfer Bitrate
[ 5] 0.00-1.00 sec 8.60 MBytes 72.1 Mbits/sec
[ 5] 1.00-2.00 sec 8.67 MBytes 72.7 Mbits/sec
[ 5] 2.00-3.00 sec 8.63 MBytes 72.4 Mbits/sec
[ 5] 3.00-4.00 sec 8.98 MBytes 75.4 Mbits/sec
[ 5] 4.00-5.00 sec 8.80 MBytes 73.8 Mbits/sec
[ 5] 5.00-6.00 sec 8.55 MBytes 71.8 Mbits/sec
[ 5] 6.00-7.00 sec 8.78 MBytes 73.7 Mbits/sec
[ 5] 7.00-8.00 sec 8.75 MBytes 73.4 Mbits/sec
[ 5] 8.00-9.00 sec 8.74 MBytes 73.3 Mbits/sec
[ 5] 9.00-10.00 sec 8.94 MBytes 75.0 Mbits/sec
- - - - - - - - - - - - - - - - - - - - - - - - -
[ ID] Interval Transfer Bitrate Retr
[ 5] 0.00-10.00 sec 89.2 MBytes 74.8 Mbits/sec 0 sender
[ 5] 0.00-10.00 sec 87.4 MBytes 73.4 Mbits/sec receiver
iperf Done.