Hello everybody,
After some research, I found a fix for my BCM4321 on Macrumors forum. Here's the link : https://forums.macrumors.com/threads/macos-10-14-mojave-on-unsupported-macs-thread.2121473/page-499#post-27158094.
So, at this point, everything is running well, and my BCM4321 from an old iMac 24 is working on the DELL E6320's WWAN port.
Could you just check again my report ? Because my notebook is heating a lot, the fan works but "mac fan control" doesn't detect any fan, so maybe there is a problem somewhere ? Thanks per advance and really I admire you for all the work that you do for us.
I posted the sendme file on my drive, because it's too large : https://drive.google.com/open?id=1v0scX0wDc-OA2aCzHN_Rfdq-9hgDNZyF