This is an issue with nearly all American props. They’re designed for A. High alt, high speed engagements, and B. CAS.
The A. means low alt/speed flight performance is compromised (and the few that do it well, e.g F6F, don’t have the engine power needed for sustained fights).
The B. means American aircraft had to be heavily armored, carry lots of ammunition, and have extra structural integrity to carry ordinance. it also means America has tons of amazing CAS options, maybe even the best from rank 1-5. Sadly, CAS doesn’t matter in Air battles as it means they’re too heavy to climb quickly, turn quickly, or accelerate quickly.
This being said, American propeller plane designs were the undisputed kings of aerodynamics, and whilst they almost never actually reach said top speed in a straight line, the combination of a strong airframe, great aerodynamics, and lots of weight means amazing dive performances.
Warthunder prop planes have two metas, low alt dogfighters, and BnZers. American planes, lacking turn rates and thrust/weight ratios, fit neither of those two. It’s also extremely difficult to bring the fight to high alts, without getting shredded by Spitfires, Bf-109s, Fw-190s, Nig-3s, and anything else with actually good climb rates, and not only that, there’s no reason for low alt dogfighters to follow you to 20k ft anyways.
So yeah, your options are A. just side climb, and hope you still have teammates left once you’re high enough to join the engagement. Maybe even snag a bomber kill while you’re up there. Or B. ignore 70% of the tech tree and only go for the supreme aircraft (e.g P-63A-5, the Corsairs, the Early P-38 and P-51, the F8F, and the very last P-51)