I think High Level D&D should just default to short planar romps. Domains and Politics is not natural aspects to is mechanics. D&D is "Go to place. Dodge the trap. Break the door. Kill the guy"..Agree. They could have those tiers, but it should be strictly optional. And to be honest, personally, if high levels shifted to more of a domain management and faction power dynamics, i would rather play Houses of the Bloodied that is designed for that kind of games. D&D just isn't good at that kind of games from mechanics standpoint.
High level D&D should just focus more on it and embrace that high level PCs can skip steps..
I remember once Jeremy Crawford saying the World Tree Barbarian would be able to teleport the party across the planes via the World Tree. Didn't make the cut.
Gloomstalker Rangers are Shadowfell focused and Fey Wanderers are Feywild focuses. Neither can travel to their respective planes.
Rather than embrace the "Planeshift, Battering Ram, Nova" nature of high power D&D, D&D runs from it.