Particle System is smooth before exporting to iOS, but then looks pixelated after export to iOS

I am creating a game where an object remains in place as its surroundings move towards it. I added several particles and effects to make it seem as though the player is moving forwards, including a trail effect.

In this scenario, a trail wouldn't work, so I created an alternative using the particle system in Unity. I made particles fire backwards from the player (the particles being a child of the player) and decrease in size over their lifespan. On my computer, this works great! When I move the player left and right (using transform.position + and - speed * Time.DeltaTime), its perfectly smooth, as seen in screenshot-1.png attached below.m

Exporting the project to my device (iPhone 12 Pro) yields a different result, and I don't believe the hardware is the culprit as the phone is fairly recent. When I move the player, the trail becomes pixelated, but returns to its original unpixelated form as soon as I stop moving. This can be seen in screenshot-2.jpg. Interestingly, if I stop moving, but the particle trail is still at a curve/angle (a little hard to explain, but basically when the trail is still slightly curved after the player stopped moving or died), the trail is no longer pixelated as seen in screenshot-3.jpg.

I am lost as to whether this is a bug in the unity software which I might be unaware of (if so, would a upgrade/downgrade fix this?) or if there's something I am missing?

I suspect it might be something with using transform.position to move the player, but using another way to move the player such as AddForce wouldn't work as the whole idea is to move suddenly with no acceleration.

Your support would be greatly appreciated. Thank you very much!

Screenshot 1: Smooth particle movement when run on PC.



Screenshot 2: Pixelated when moving left/right


Screenshot 3: Smooth particle movement if I don't move the player but is moved by another force (explosion force, in this case).

 

Sorry for the late reply,
I am on Unity version 2021.1.23f1