the universe of LotR is called Eä, which means “being.” Ilúvatar is not in Eä, he observes it from outside, in the Timeless Halls where all the Ainur originally lived before creating Eä. all of the Ainur who entered Eä did so together at the beginning of time, and cannot leave until the end of time (except for Morgoth, who was banished to the Outer Void). so Gandalf wasn’t hanging out with Ilúvatar, but he was in Valinor until about 1000 years after the events described by Elrond
the universe of LotR is called Eä, which means “being.” Ilúvatar is not in Eä, he observes it from outside, in the Timeless Halls where all the Ainur originally lived before creating Eä. all of the Ainur who entered Eä did so together at the beginning of time, and cannot leave until the end of time (except for Morgoth, who was banished to the Outer Void). so Gandalf wasn’t hanging out with Ilúvatar, but he was in Valinor until about 1000 years after the events described by Elrond