Looked up the trailer weight and you didn't get taken by the car dealer.
Did you actually tow the 5ver with the F150 and have issues, or just speculating based on "reccomendations?"
Presume by your post it is a new 2019? F150 or near new and "beefed up" means max tow or max payload or both?
If so, that trailer is in that truck's wheelhouse, albeit closer to the upper end than the lower.
I see them small 5vers behind GM and Ford 1/2 tons every day on I 90 and the pilots' knuckles aren't white. Lol.
And they all have WA, MT, ID, OR tags and they're either actively going up or down a Mountian pass at the time and most likely many others before and after.
All that said, a 3/4 ton will handle the pin weight better, but not necessary. Not a game changer, IMO.
2016 Ram 2500, MotorOps.ca EFIlive tuned, 5” turbo back, 6" lift on 37s
2017 Heartland Torque T29 - Sold.
Couple of Arctic Fox TCs - Sold