It's made in Godot 4. But I'm not really 100% sure what you mean honestly, I do some times feels like certain actions kinda feel more stuttery than the FPS indicates, but since it's very mild for me I've kind of forgotten about it. I'll try to check against some older versions to see if I can maybe figure this out.
Did you try enabling vsync or capping FPS or fiddling with some other settings like disabling movement wobble?
If you have any other details that might help, like if disabling any settings improves it, or if it's better/worse in certain situations, please let me know!
edit - also, I do have very limited FPS cap options right now, is it possible you have a different monitor refresh rate than any of the available options or something?