I take a bit of a Chekov's Gun approach to world lore. It can jar the pacing of a game to force a full creation myth onto the players mid-game, only to have it never be relevant. Instead, I try to make certain world set pieces relevant and then weave them in.

Right now, creation myth is exactly what I'm working with in a game I'm running. As it turns out, the myth that the gods created the world and are responsible for certain things is going to turn out false. The juxtaposition of the myth and the truth are ultimately going to be important to the story, exposing a history of astral beings that predate the gods and unveiling the BBEG's true plans.

As such, it's been important that I gradually immerse them in the concepts and lore surrounding the stories. Slowly over the course of the campaign, they've been introduced to the various planes that are relevant to the story and told small stories related to them.

For example, they met a "Brass Elf", which is a nomadic culture of High Elf in this setting with Efreet blood in their lineage. I used her introduction as an opportunity to lightly touch on the Feywild and Brass City. They were also seeking her Shadowfell expertise, and so it was a chance to relate and contrast the two planes and discuss their relationship to the greater cosmos. I didn't have to dump the info on them, because they're topics they've gained a passing familiarity with before and will see again as time goes on.

That's not to say some idle world-building can't happen. I also brought up the lost homeland of the brass elves far to the south -- once a massive desert, now hundreds of miles of glass. It's not important to the plot, so I didn't spend meaningful time on it. They'll probably never even see the place. But it was tangential to the situation and offered a chance to color the world a little without going out of my way.