Gfrktyl

In D&D (Forgotten Realms) lore, is there any kind of answer for how long it takes the soul to leave the body after death? If not, is there any answer implied by other rules or effects (such as resurrection spells)?

The reason I ask is because I think that this might be the reason that revivify does not require the soul to be willing whereas other spells do (since revivify must be done within a minute after death (Basic Rules, p. 104)).

Though I am asking about 5e, answers supported by earlier edition lore can be considered.

The rules don't specify; revivify's limit is a good starting point

As with a lot of things, the D&D 5e rules leave a lot of latitude for interpretation. @Aviose came up with a good conceptual model in a comment on an answer to a question about souls in 2015.
_{I'm taking this opportunity to pull it out of a comment and put it into an answer that it fits.}

Best way to view revivify working is simply stating that it takes
about one minute (maybe more) for the soul to leave the body upon
death. Consider that the in-world time to brain-death and look at revivify as an advanced form of CPR.

Of interest: I was looking in my 1e and 2e AD&D material and find that the explicit link between souls and raise dead / resurrect spells comes from 3e and later. I'll follow up with BECMI/BX info when I get back to where that is

An example of the immediate departure of a soul in FR is Kelemvor's soul:

Kelemvor's soul was absorbed into Cyric's sentient sword, Godsbane, in the moment he was killed on top of Blackstaff Tower.

Given the agency and nature of the sword involved, that may be an exception rather than a rule (This appears to be during the FR's AD&D 2e continuity, Prince of Lies).