Another fan of Rotella T6 5W-40 here. I've been using it since my 1st oil change (~8K, 2nd change was ~15.5K), and my truck now has 17,800 miles and continues tracking to ~10K drain intervals but I have decided to change every 7,500 miles because of towing my boat with it. I am planning on doing my next change ~22.5K.
I order my OEM filters from here -->
https://www.dieselfiltersonline.com/fl2081-jl3z6731a-2018-ford-f150-3-0l-powerstroke-diesel-oil-filter.html (Note: ordering 4 at a time seems to be the sweet spot for shipping costs).
Rotella T6 is readily available locally, and Walmart carries it at decent pricing.
I then take the OEM filter and the Rotella T6 5W-40 to my local Ford dealer and the boys change my oil for $26 using my provided supplies.
I go to play in a monthly home poker game where a mechanic from my Ford diesel shop also plays in, so have gotten to know him over the last 2-3 years. I've probably asked him 100 questions about our trucks since taking ownership of mine the day before last Thanksgiving. One of the questions I did ask him was oil, and he instantly replied Rotella for what it's worth.