I'm currently trying my best to make my phone<->car connexion work, and ... welll ... I'm here for help guys

Let's start with the car :
It's obvisouly a C3, from 2017, SHINE. I got a nice screen and radar on the back.
VIN is : VF7SXHMZ6GT537594
I just updated my NAC to the last version, as recommended everywhere with my kind of issues. That means current version is 21.08.87.32_NAC-r1
I have a Galaxy s8+ (SM-G9550) fully updated, with the last android auto installed, and mirror link enabled in the settings.
I also downloaded the "Mirrorlink" app from "Flapavv", some people said it could help ...
I'm using a brand new USB cable, with works perfectly with the PC.
I'm in France, the car is french, the phone is in french, Google play is also in France region.
Now here is what happens :
The car only let me choose between "Air-Play" and "Mirror-link". I don't have an "Android auto" option, even if the C3 2017-+ is listed as compatible here : https://www.android.com/auto/compatibility/. Is it the case with everyone ? I'm fairly sure I saw some youtube video with people with the same car as me, and with the thirds "Android auto" option ...
So anyway, mirror link is fine. I plug the USB, select mirror link on the car, get a connexion screen, all seems fine.
Then my phone turns in "Mirror link mode" (lower resolution, and a black screen saying "Mirror link connected"), but the car says "Your mirror link device could not connect".
And I cannot figure out what the hell happens here. The phone says ok, the says it's not.
If any of you guys had any idea, that would be awesome !
Anyway, thanks for at least taking the time to read this far

Best regards