Thank you so much! And yeah the camera thing is already fixed and ready to be uploaded after this jam. (I haven't playtested this game on a pc once, I don't know how bad the jittery gets because on mobile it looked fine) And I added extra tweaks to the camera offset so it doesn't cause motion sickness.
Actually i figured out on more technical standpoint is that, the Camera2d doesn't follow the player through physics so it was using _process which ticks every frame while _physics_process ticks 60/s. Which means on higher framerate (forgot to cap it) the camera smoothing moves faster than the player thus the jittery (and thats why it works fine on my phone because i capped it at 60hz).