@vaartis Maybe I can help, what do you mean by jaggy?
Line renderer is fine for me.
Here's a circle using a line renderer in local space.
And some other shapes too.
(Ignore the project in the background)
@vaartis Wait... why are you looking at a ticket from 2018?
What version of Unity are you using?
@vaartis Trail renderer isn't too bad either, though I wouldn't recommend it, as it is a bit too simple.
Still, are you on some ancient version of Unity or something?
Anyway, when it comes to trail, if you want something nicer looking, and more customizable, the way to go is particle system.
Set the emitter to emit only on distance, and there you go.
@vaartis There's also the Visual Effect component that is similar to a particle system, but runs on the GPU (if memory serves).
I don't have much hands-on experience with it though.
And good luck with whatever you're making.
@vaartis Here's a little proof of concept.