Hi,
I've been diagnosing and troubleshooting more, cause i've talked too fast and ExitLag didnt resolve my issues.
Though i think i've come out with a solution, tested it, and so far i haven't had packet loss (client side) again.
After investigating further more its seems, my issue comes from an incompatibility of one of the features of my network card (Killer E2500) with my new ISP (Free, one of the few France ISPs).
https://www.speedguide.net/ was really very helpful to troubleshoot. This site is awesome.
A year ago i had to remove the "advanced stream detect" feature of the Killer network card, which is a known issue already.
Now i had to download the .INF driver file from Killer networks site, remove the driver, block the Windows Update trying to download the drivers again.
Then downloading TCP Optimizer from speedguides, run it as admin, select my network card and applying the settings in the attached screenshot.
Hope that helps ! 🙂