Is it the GSI image with OTA by @fwg-cag? If yes, I don’t think it supports FP3+ yet. So I would first try installing e.g /e/ to test if it works better.
In any case, it’s an unofficial OS, so don’t be too surprised if you have bugs. So I would first consider the bug is on the OS side.
Otherwise did you try another cable? One that allows data transfer?
I did not use another cable (it’s the same that I used with my OnePlus 5T). I will check with another. Btw I use the same cable to transfer my music from my computer to the FP3+.
Thanks for your help, I will give a chance to /e/, but I don’t like the « apple » copy interface. I leave the Apple world 5 days ago now…
Are you talking about the launcher only? Because the launcher can be easily changed, just download another one (e.g Lawnchair) and set it as home app in Settings→ Apps and Notifications→Default Apps.
All I can say is that Android Auto works fine on the official Fairphone 3 image as I used to use it a lot, so my best bet is that, especially it being a Google application, you’re lacking the official Google Play Services and microG isn’t good enough in this case.