Unity WebGL 60FPS on Windows, 30FPS on MacOS

Hello there!

[project]

I am starting with simple 2D game. It will be build for WebGL. Right now I have a simple scene with background and 2D rotating sprite - just it, nothing more. I setup server, open it on Windows 10 and Edge, I have got stable 60FPS in my browser, but my friend who is working on MacBook, has a really bad performance max 30FPS but it is jumping from 24-30FPS.

[In project]

I have a background spitre 1920x1080, 2D Hexagon Sprite rotating with simple code:

 > transform.Rotate(Vector3.forward * speedRotate * Time.deltaTime);

It is build as WebGL in 900x600 window.

[I have tried]

I have tried using Canvas, but it is even worse. I have compiled ready project from assetstore, more complicated - 200mb file to load for browser, and it is working in 60FPS on Mac with no problems... Mine is build is 10Mb.... and performance is awful.

[Question]

How can I achive 60FPS on Mac?

Is there any specific project setting for WebGL?

Any tips for WebGL projects?