I changed 1st oil at 500 mi, 2nd at 1500 mi, 3rd at 3000 mi, 4th at 5000 mi....currently at 6400 mi and will be changing at every 4500 mi. I had 4 gens of F150s since 2000 and never experienced cam phaser or any other engines issues.
I have had 4 EB 3.5's, and my brother in law has one as well. No motor issues ever, and we always do full synthetic 10k oil changes
2013 SHO EB-3.5 sold at 50,*** miles
2014 Explorer Sport EB-3.5 sold at 110,*** miles
2012 F150 EB-3.5 has 120,*** miles
2018 Explorer Sport EB-3.5 has 19,*** miles
2018 Raptor EB-3.5 has 20,*** miles
Spend your money how you want. But I have experience with 5 of these motors using 10k changes. You are in no danger of breaking things following recommendations.