Ancalagon
Dusty Dragon
Here's the thing: lifestyle expenses and downtime both can be used only in particular types of campaigns, ones where you have non-adventuring days.
In a campaign where the PCs have a clear and defined goal from the beginning: take down the BBEG, the PCs will pursue this goal without taking time off. Even less so if there's a ticking clock.
From level 1 to 20?!?
Even if it's always "in game", there should still be downtime...
"you traveled with the merchant caravan for the next 2 weeks as you journeyed to the kindom of Somethingland to hunt for clue to help you find the McGuffin Axe, the only weapon able to harm the BBEG"
"You spent the next 3 days recovering from your wounds and researching the tomes of the ancient library"
etc etc.