Basically just this, MSAA. The MultisampleRenderTarget makes it available for render targets as you see it on canvas without postprocessing. But it depends on the hardware and the settings.
FXAA is the best option for performance and quality still. Other AA techniques are more expensive but you can give them a try if FXAA doesn’t fit your needs.
Yes, but actually no. MSAA is more efficient rendering subpixel only at edges of triangles but it also isn’t guaranteed that it will be applied, nor which level - it does look prettier but some of your users hardware might not provide it, and then there is no AA at all.
Supersampling will give you a flawless result with terrifying performance since you’re going to render at 4k for a regular 1080p screen.
FXAA is very cheap compared to all other options and also one for mobile. The example scene you linked also isn’t exactly the best case scenario, in actual scenes with less heavy contrast and diagonal edges it becomes much less visible.