I made a project as simple as possible to illustrate my issue, you can access the repository here if you want to try it out.
Basically, I experience stuttering even on the simplest project whenever I use PhysicsProcess. It's most noticeable on Android, but you can notice it a bit on a computer as well. It seems I don't have the issue when I use Process instead of _PhysicsProcess, but then I end up with physics working differently depending on the hardware I deploy the project to.
Project's structure:


Player is a KinematicBody2D with the following C# script attached:
`
using Godot;
public class Player : KinematicBody2D
{
private const int Gravity = 100;
private const int Speed = 750;
private const int JumpForce = 1600;
private Vector2 _motion;
private Vector2 _up;
private bool _jump;
public override void _Ready()
{
_motion = new Vector2();
_up = new Vector2(0, -1);
_jump = false;
}
public override void _PhysicsProcess(float delta)
{
Move();
}
public override void _Input(InputEvent @event)
{
if (@event is InputEventScreenTouch input)
{
_jump = input.IsPressed();
}
}
private void Move()
{
_motion.x = Speed;
_motion.y += Gravity;
if (IsOnFloor() && _jump)
{
_motion.y -= JumpForce;
}
_motion = MoveAndSlide(_motion, _up);
}
}
`
I tried a bunch of different things, but none of them solved this issue (e.g. toggling pixel snapping, setting the Camera2D's process mode to physics, playing around with all sort of settings...).
I've spent so much time on this even though the project is literally 45 lines long. What can I do? I guess I'm doing something wrong, but what?