"source resolution" is NOT going on Mac (air m2)

Hello,

Sorry for my verry bad inglish, i'm French.

So, i've 2 computers:

- MacAir M2

- A PC Dell Laptop (old, 2013 model), with a 3200 x 1800 screen resolution.

My dell is under Linux Mint / windows.

I've a fiber connection, (speedtest result is about 900 DL / 650 UP, so verry good) with ethernet.

I've paid for Nitro. So here is the problem:

If i stream from my dell computer, i can select a "source" resolution, and the result for viewers is absoluty perfect, there is a REAL difference beetween "source" vs "1080p". Perfect stream under windows or linux.

But, if i stream from my Mac Air m2, the result is verry bad: there is absolutly NO difference beetwin 1080p or "source". absolutly none and the stream is so bad !!! The screen resolution of the Mac Air m2 is  2560 x 1600 so it'not normal i can't see no difference beetwin source or 1080p. The result is the same with an external 4k monitor.

I've check / unchek the material acceleration video option, it's the same.

So, my question is: does the "source" resolution is working on mac ? Is it a specific problem for Apple Silicon's mac (m1 / m2)

Thanks for your help, and sorry again for the bad inglish !!