I’ve got no good answers for you. 
I finished the Hell’s Rebels Players Guide module for Fantasy Grounds. I finished the maps for the first two encounter areas, but still have to do a map for a mini-encounter that happens in between. I started working on the gazetteer for the city in Fantasy Grounds and that’s when I starting having another GM’s existential crisis…
What if the players go to one of these cool places before they’re supposed to? Like 3 modules and 10 levels before?
What if they go off the rails to some other place that’s described in the gazetteer but actually isn’t part of the adventure?
There’s martial law (and a soon to be rebellion), how come it’s business as usual for shopping, sight-seeing, and just walking the streets? In armor? Carrying weapons? Wearing holy symbols?
The party knows at level 1 know who the big bad guy is, what’s stopping them - besides meta-gaming mechanical knowledge - from going after him at the beginning of the adventure?
How do I not make this feel rail-roady? There’s a huge city of 12,000 souls to explore but you can’t actually explore it and the party is constrained to certain areas at certain times.
In the grand scheme of things, not that big of a deal, but the recently announced Bestiary 3 has the official stat block of a creature I need in the first module. Will you all notice?
Speaking of stat blocks, there’s a f**k ton of humanoid type NPCs that need PF2 stat blocks for an urban adventure, where the heck am I going to get those or how much time am I going to spend on those?
Cities are huge. My mini-OCD means I need maps for every available contingency. How the hell am I going to get that ready?
No good answers, only more questions.