Quick answer: Unreal CharacterMovementComponent's AirControl ignored during jump? Air control applies between jump start and apex; outside that window, ignored - tune the window.
Player jumps; mid-air input doesn't steer; movement is fixed trajectory.
Tune AirControl property
0.0 = no air control; 1.0 = full control. Default is 0.2; raise for steerable jumps.
Or use AirControlBoostMultiplier
Boost when player presses against direction. More forgiving.
Verify in PIE
Mid-air input; character should turn. Lack of turn = the bug.
“Movement properties are tunable. Defaults are conservative.”
If your character feels stiff in air, the AirControl tuning is the first knob. Test deliberately.