I was about to edit my message about it.
I just tried to give the client as much permissions as possible (firewall, anything connection related, etc), same result.
To be sure I even tried on another random server since I never tried before (the csgo on the main page I think) and I can’t stream either.
Edit: Checked again, to be sure it was the right path and not ts3, but yes ts6 have every freedom as far as I know.
I tried closing ts3 to be sure too.
Edit2: Ok so … Since it was installed and launching as administrater by default and actually never tried without that.
Launching the client without that, it’s working almost flawlessly he doesn’t like my monitor with hdr, it’s flashing, i can life with that for now.
It was actually to much freedom, he couldn’t decide what to do and chose to stay still to avoid responsabilities.
(Just to clarify; right click priority > compatibility tab > Execute as administrator unticked > working now)