Oh BEEP BEEP NO. If they are planning and sticking with A plan, again ONE hour. MAX. If they are trying come up with the perfect plan to reduce the hit point take down to zero, the monsters have eaten two other adventuring groups and have left the building.
I was dming ONCE for Friends of a friend. It took the two experience D&Ders 2 hours to go left or right, in a Alice in wonder land dungeon. The poor newby who became my best man never played D&D again.
This is incoherent to the point where I don't even know what you're talking about.
You seem to be complaining about:
A) People taking "an hour" to decide what to do in combat. Maybe? I have no idea really though what "the hit point take down to do zero" means though.
B) Two "experienced" players apparently taking two hours to decide whether to go left or right. Which is obviously completely insane. Are sure they weren't "doing a bit"? Because it kinda sounds like they were "doing a bit". If it wasn't a bit or a prank, then why on earth did that happen? Were you playing with Laurel and Hardy? You know what those two are like.
So...?
Any your examples and all-caps have nothing to do with players coming up with an elaborate plan to deal with what appears to be a complex situation relating to an entire dungeon.
There's a very cool 5e hack that uses mechanics from Blades in the Dark, it's called Here's To Crime by Jimmy Merrit. Obviously very useful for urban intrigue, but the important thing is that is has a nice system for using inspiration to trigger Blades-style flashbacks. Adding a flashback mechanic can work wonders for cutting down on planning time because the players know they'll be able to shore up the wonky bits as they go so there's no need to plan everything in excruciating detail.
Does it work exactly like the Blades in the Dark system or does it have a bit more subtlety to it?
I first used a flashback system in D&D in 2012, back in 4E - there was an adventure in Dungeon 200 - Blood Money by Logan Bonner - which was about you pulling off a heist from some awful dude who owned a castle, and that used a flashback system wonderfully, and in a very limited way, so you could use it to fix mistakes in the heist, but wasn't the whole of the heist.
Blades in the Dark is one of those games, that if described, sounds 100% like my sort of thing, but the absolute insistence that you don't plan the heist
at all, like not even slightly, you just go into face-first and then use flashbacks to retroactively plan it made it a total flop for me and the rest of the group. I mean, c'mon. Let us plan it a bit - then we can use flashbacks to fill stuff in! We always try to play PtbA games the way they say they're meant to be played but that a real thumbs-down from us, and a very surprising one too.
I'd love to see a good flashback system for 5E, that wasn't intrusive and didn't insist that all/most planning should be retroactive.