Mesh moving and rotating forward and backward when flying up and down (UE 5.4)

Hello!

I’m a beginner and I’m creating a prototype project where you can fly as a bird.
I followed a few tutorials and made it so that if you press Space while in bird form you can fly up, and when you press Left Ctrl you will fly down.
Works fine if you also move with WASD and mouse (camera), but if you don’t move and just press Space or Left Ctrl, the character moves up+forward and down+backward (with a corresponding rotation).
How can I make a character (bird) stop flying forward/backward and look in the same direction when he’s just flying up and down?

Can’t figure out how to fix it. Pls help!

Videos of the issue (from 13 to 23 second I pressing only Space and Left Ctrl):

And also screenshots of BP:

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