There should be an Unreal toggle in the Duty Finder settings. Any fight would have an algorithm scale up their level/HP/dmg to current max level.

(When Unreal was first announced I thought the devs were testing the waters for this exact idea. I am not sure this is actually the case anymore, but it seems like a shoe-in for future-proofing the next 10+ years of FFXIV.)
  • Past Unreals would serve as a template for a scale-up factor, a formula applied to boss health and damage output and taking into account things like ilvl requirement on release and expansion quirks (i.e. no ARR/HW crits).
  • Since these Unreals would not be relevant for endgame progression, fights that are too easy or hard could be manually scaled in smaller patches based on feedback with little effect on hardcore players.
  • I am not sure whether having fights scale to either a fixed iLVL (like current Unreals) or to current Raid BiS iLVL would be better, since not being able to use current gear/materia is always sad. The tradeoff is the Unreal algorithm would have to account for player progression every major patch, which is more up-front work.
  • Completing past fights (Savages, old Ultimates) could offer unique rewards for clearing them on Unreal (mounts, titles, Adventure Plate designs).
  • Although the current Faux system is nice for rewards and weekly content, this could still be implemented by having a weekly Unreal target for bonus Leaves, like the Blue Mage Log.
Doing old content again would be incentivized for both new players, who could experience things like the fabled Living Liquid in all its HW glory, and older players, who could get rewards and replay memorable fights for fun.

lv70 Ultimates especially have not aged well for dps checks/difficulty, so these would also be massively improved by this option.

Please consider! Thanks! :)