It is impossible to balance D&D. Because D&D is split into two separate "time" things-- mechanical ones and narrative ones. And those two do not work well together.
The "Encounter" is purely a mechanical time thing-- an Encounter starts, you have certain abilities you can only use a certain number of times during that encounter, then the Encounter ends when the mechanical result has been accomplished. At that point the number resets, and the next time you have a new Encounter, you have all your encounter stuff again.
The "Day", however, is purely a narrative time thing-- at some point in the narration of the game a Day begins and you gain certain abilities you can only use a certain number of times during that Day. However, unlike Encounters, there is no fixed mechanical point to tell us that a Day is over. Rather, it is the players and DM all collectively deciding together "Okay, we are ending this Day and will take a rest". For absolutely no mechanical reason. The mechanics do not ever tell us that a Day has ended and it is time to reset... it is always just a choice based on the story of the game when the Day ends-- based upon the logics of the story telling us a certain number of "hours" have passed (again, a narrative time thing, not a mechanical one).
As a result... a Day could include one Encounter, it could include two, it could include four, it could include 6-8 Encounters, or it could even include NO Encounters. It's entirely based upon the narrative decision of the group to reset things. And what's more... unlike Encounter abilities that only operate within the said demarcated "Encounter"... "Day" abilities can (and often will) be used outside of individual encounters during the narrative downtime between them. The Story around the Encounter (or fights) if you will. And a lot of those Day abilities don't even have in-Encounter use-- they are specifically designed to be used ONLY outside of Encounters.
And let's not even get started on "at-will" abilities... abilities that can be used all the time as often as you want both within Encounters and within the narrative downtime around the Encounters during the Day. That's now a suite of abilities that can "break the game" for certain tables depending on how they play (and why there are tables out there that hate Cantrips as a thing for instance.) When a feature can be used both within the Encounter and during the Day... you can't balance that against other strictly Encounter abilities and strictly Day abilities.
This is exactly why I don't worry about "balance" anymore, because I know it's going to be a fool's errand. Yes, I might have Encounter abilities that only work during Encounters and are reset on a set schedule... but when I also have Day abilities that can be used within those Encounters too and DON'T reset on a set schedule... and I have at-will abilities that can be used all time within Encounters and Days and never have to be reset at all... there's no way to be able to calculate what that "balance" can be. Balance requires strict calculation. But when some many functions occur on schedules that aren't strict... that screws the calculation up. So all that's left is just playing the Encounters as they are and treating them as merely one more Narrative unit that drives Story forward.