Just for avoidance of doubt, you don't rule out that there can be constraints in place even where DM gives up none of their otherwise traditional-mode authority to players?
In which version of D&D? I think that the DM is constrained much more in some editions of the game than others. Or at least, is meant to be with the game as written.
If you mean 5e, then it's difficult to answer because the authority of the DM is never explicitly stated... but there are a lot of statements that indicate that they have total authority over the world, the rules, and the adventures. If we take those to be accurate, then the answer is no, any constraints on the DM removes some amount of their authority. It may not always be given to players... sometimes it may be given to the dice or may just be removed... but it's always a reduction in DM authority.
I guess I don't consider players authorial freedom is necessarily the same as giving up authority. There's a lot of options there. For example, the DM could give everyone an area, region or organization to create but then once the campaign actually starts the DM has full control over whatever the players created.
Take a look at what you just said here. "The DM is not
giving up anything, he's just
giving an area, region, or organization..."
I do this quite frequently with PC's families and people introduced in their backstories. I may ask for details on the PC's perception of the NPC, but I maintain control of them so that even the player that created them can enjoy interacting (instead of controlling) those NPCs.
Of course you can always go to the extent of changing who sits in the DM's chair (which I've done) and many other options between. Not sure it matters what terms you throw at it. If you want to call it "constraints" on the DM so be it, but there are a lot of options.
Right, but you're always talking about voluntary or optional things. All of this depends on what the DM chooses to do or allow. Those aren't constraints, those are options.
Constraints are binding. Think of rules that we normally accept... the goblin has an AC of 15, and I've rolled a 19 to hit... I hit. The DM is constrained to acknowledge this. If I cast magic missile, it works as described in the spell description. If I have the Sentinel feat, and I hit an opponent with my opportunity attack, it loses its remaining movement.
These are (barring any rule zero bunk) constraints on the DM's authority. This is where the rules tell us what happens, not the DM.
There aren't really any clear constraints on the DM when it comes to authoring the fiction of the game. Yes, many DMs will typically allow a certain amount of leeway during character creation, but that's not always the case. I could say I want to be a member of the Elk Tribe, and you might then say "whoa, whoa there is no Elk Tribe... only the Bear Tribe and the Wolf Tribe exist in my world... pick one of those" and be perfectly within what many consider your authority as DM.
It's that "right to edit" you're always mentioning.