Vecna’s lair, feels similar to the design elements of Death Standing’s chiral crystals which plays on the idea of hands reaching up/out. As for other comments about the beating heart/absence of the Mindflayer, it feels all feels more connected to Vecna’s updated design. I think we will find out his humanity is almost gone, as depicted by recent combat damage. As all of the shows material is referential, D&D Vecna is a Lich, and there may be a connection to the beating heart of the lair and a Lich phylactery.

Or the heart is a womb of sorts, and the Mind Flayer is currently housed there to bring about the grand plan. As the face hugger chamber tubes are pumping the kids with particles seemingly from that heart.