No answer on the networking forum yet. I cannot try because I don't have a Pi4 yet. It seems possible. An easy test would be to test whether this command will work on Pi4:

raspividyuv -md 7 -w 640 -h 480 -t 0 -fps 90 -o - | nc someIp somePort

and on someIp server service listeing on somePort just storing the data received. Because yuv has 12bits/pixel which is a bit more than the 10bit/pixel of raw Bayer, the command produces a 316Mbps stream of data for v1 camera (732Mbps for v2 camera when recording with "-fps 180"). For testing the service on someIp can be as easy as:

nc -l somePort > foobar

You should be fine with RPi3B+ internal gigabit NIC

https://www.raspberrypi.org/forums/viewtopic.php?f=63&t=2085...

pi@raspberrypi:~ $ sudo iperf3 -c XXX.XXX.X.XXX

[ 4] 0.00-1.00 sec 37.9 MBytes 318 Mbits/sec 0 257 KBytes