Villains Becoming Gods

[Xihirli]

We're all familiar with the trope wherein the villain of the work is trying to become a god.
My villains are pulling a Myrkul/Bhaal/Bane with less bravery, tracking down the remnants of gods that are already dead in order to access their divine sparks and perform a ritual.
Bearing in mind that, if they play smart, the players could learn how these rituals are done, how would you go about it? What sort of material components would be necessary, and how long - and easy to interrupt - would the ritual be?

[Zhorn]

Tomb of Annihilation, Acererak serves as a perfect example of creating a god with the ritual of the soulmonger and Atropal.

[Angelalex242]

You could always borrow the plots of video games.

I seem to recall a gentleman named Sephiroth plotting to slam a meteor into the planet (with a 10th level spell?) and absorbing all the life to make himself a divine spark.

[Maan]

You could always borrow the plots of video games.

I seem to recall a gentleman named Sephiroth plotting to slam a meteor into the planet (with a 10th level spell?) and absorbing all the life to make himself a divine spark.
Or Morrowind.
That's old enough that your players are unlikely to have played it, if you are younger than me.

[Unoriginal]

The Yuan-ti Anathemas can become gods if they go through rituals, notably requiring the sacrificing of a lot of snakes and (IIRC) bathing in their bood.

Maybe your villains stole the knowledge from the Yuan-ti?

The components for the ritual could also require taking things from titans and/or demigods.

As for how long or difficult it is to interrupt, well, it depends entirely how hard you want your campaign to be.