There's no recipe for Orb of Origin now, that players couldn't regret their choice at the beginning of the game. However, a recipe for such a thing should be expensive.

Here's my recipe for 1.16.1:

□I□

IAI

□I□

□: None;
I: Netherite Ingot;
A: Nether Star


If you think it's too expensive, you can change the Nether Star to Heart of the Sea, or change Netherite Ingot to Netherite Scrap.

The orb of origin not having a recipe is intentional. The origin being unchangeable is true to the idea of the mod, but at the same time I see why people would want the orb to be obtainable. That's why I encourage people to add their own recipe via a data pack, as I don't want to prescribe how expensive or cheap the orb should be. I've heard of people making the orb quite expensive with a Nether Star as the ingredient like you proposed, but I also heard of others who added a recipe that was way cheaper.

I hope this sufficiently explains why there's no recipe for the orb by default.