Knowing what we know about just about everyone that posts on an internet forum, why the hell do we look for a reason to let the trumpet be at fault? I mean, let's get serious. How much hardware is out there that REALLY holds a trumpet player back?
Notes above the staff require superior BODY USE and consistent intelligent practice, then they become second nature. High F is naturally a decent note when played with the first valve. It is still a fairly strong partial like the F# with 2 and G with 0.
If it is squirrely, we need to look in the mirror, not in the tool box!