Put me on the list of "Demand a NEW Long Block" posters. Also, something in the engine bent that valve and at the least I would want to view and take pictures of that cylinder and piston! If there is so much as a shadow on the top of that piston, that entire engine needs to come out!
Having this type of work done while an engine is still in frame is a lot different from building one on an engine stand. To many things can cause a Tech (not I did not us mechanic as I do not think they exist anymore at dealerships) to make what might be a small mistake and cause things like leaks.
I purchase a Used Harley Davidson that had a Brand New Factory Remanned Engine with 0 miles. HD produces these engines with the original serial number. After riding is for a total of 10 miles it shut down just like you turned the key off. No noise and the engine spun fine. After the Dealership spent several hours trouble shooting it they found a problem with the keyway on the cam shaft. The notified HD and they were told to crate that engine up and send it back and a new Reman would be sent out. If a Company that's as tight with a $ when it comes to warranty work did this FCA should!
OP, I hope you can get this settled to your satisfaction and get back to enjoying your new Truck!