Occam's Razor suggests a reset is most likely, so it seems a safe assumption.
Occam's Razor doesn't even apply to stories written by fiction writers (not minding it's not a shortcut to an answer even when it does apply). If anything, a reverse of it might be in order because the writers actively like more convoluted answers (but then so does reality from time to time, like I said – not a shortcut).
We don't know how the fingersnap will be resolved, and we shouldn't make big assumptions. Time travel is likely to be involved, yet not because of any razors, but for other unrelated reasons:
a) It is already involved in the solution (in Infinity War)
b) Scott, and even Strange who is a known time travel guy, have higher name recognition with own namesake films than Nebula
c) Involvement of the Quantum Realm has been hinted both in rumours, and in Ant-Man and the Wasp's post-credit scene, and – if you read too much into it – the trailer.
However, that still amounts to little, because we:
a) We don't even know if the QR enables travel back in time (I don't even recall a suggestion it did), and if Strange gets his Time Stone back we got the whole Infinity Gauntlet back. Since we're definitely tired of monoliths, those are the only two time travel mechanisms that are still on the table.
b) Getting the big muscle, including Captain Marvel, any time shenanigans will still be only part of the solution. Wanda and Danvers need to kick some ass together.
c) Time reset isn't the only possible time travel option; and we only know how AoS did time resets – it might work differently here. (Whatever suits the plot, really)
c) Time reset won't bring Gamora back – unless we got my joke suggestion that Scott takes the Soul Stone from Red Skull to destroy it. Damn, Scott, your daughter's ants already have a soul, you don't need no goddamn Soul Stone to fix them.
Quiz time: What happens if cryogenically frozen Fitz in space got dusted by the fingersnap, then both the futures in which he got dusted and he got invited to travel to get reset? What happens to the timeline in which Fitz got dusted, leaving Earth destroyed killing Thanos in the process, before he could dust anyone?