Solved my issue with lagging vector icons by putting them all into separate canvases, so my game won't lag anymore. However, the Unity editor still lags.

Soon I will build it and test in production environment

I think the bug is likely caused by marking dirty the entire canvas as shown in the video above.

@trollingchar Generating the raster images on the fly won't work because you scale them when they're in the UI, is that it?

I'm afraid that's what Unity does!

The package's source code seems to build batch of triangles, not raster image

but who knows what Unity will decide to cache for optimization

Go fast and ... that's it, basically.

With separate canvases, the problem disappears, I'm 99% sure that rescaling is an inexpensive operation itself, but everything on a canvas was marked dirty and that operation took hundred times longer

maybe it's possible to avoid rebuilds altogether if I will rescale not svg, but the container with canvas

Working with Unity built-in components is like alchemy - you can get unexpected things when mixing them or not mixing

That thing is growing so big that they have issues of big companies. Left hand is getting too far away from right hand and ... oops!

Which thing?

I assume he was referring to Unity.

Yes. Unity. It's getting big.