I’m in the exact same boat as you were, except I even brought my truck to the dealer to have the modem reset. They did, and the tech was able to activate the truck using his phone, but then when they turned the truck back over to me, no luck.UPDATE!
I noticed what appeared to be a comms icon on the upper right side of the 15” display. I then opened the FordPass app and saw “Modem Active” status. It still would not activate so checked support articles and found a method for doing a FordPass master reset and went through those steps. After that completed I was able to fully Activate.
Do you happen to have the link(s) to the FordPass Master Reset steps? All I can find online is related to Sync 3.
Thanks in advance!