Download speed on MacOS slower than Linux or Windows

Just upgraded my new office network with new cables and new devices. All network is on 2.5G.

I figured out that download speed (the upload is ok) on my Macbook Air is slower than a Linux or Windows device.

I made some tests with iperf3 and here are the results:

iperf3 on Mac is directly connected to my Ubiquiti UGC-Fiber router. As adapter I'm using an Ugreen Ethernet USB C 2.5G.

I used the same adapter and the same cable to connect the Linux and Windows laptop and they show 2.35 Gbits/sec in both directions while on MacOs the upload is just 1.95 Gbit/sec.

MTU is set to 1500 on both MacOs and my router.

I also have a 2.5/1.0 Gbps fiber connection and the download is slower the Linux and Windows as well.

Why those discrepancy?