Switch between 2 games?

Can you start a game on Xbox and then another one that you can always switch to without the other one always having to load?

No that doesn't work.

It is not a pc. It's a console.

It is impossible to skip loading times.

This is actually possible on the One, but not on the new Series X.

It is called Quick Resume there, and it even works with several games at the same time. And even after switching off or removing power, the games keep their current status.