it had already all the time limit increases
You can unlock more Seals at The bathroom. As far as Positive Time Seals go, there are 11 (you start with 3).
As for your dungeon generation, it really depends on what templates you are playing on. Different Seals are more important on different templates.
Template descriptions are visible on loading screen, break room, and template tooltip in hub area.
You're talking about empty wings, so I guess you must be talking about either "Loop", or "Two Paths" templates.
Loop example:
Heart Rooms in Loop template can connect to either green path, orange, or both, so in theory, you could reach the Magic Mirror without ever seeing heart rooms, but that means to get there was just one room after the other, with every room just having 2 doors. On the other hand if you found them before you got them, you can easly narrow down your search later, as in you can decide if you can ignore one half of the dungeon. It's actually one of the easier templates.
Two Paths example:
That one is harder, because all Hear Rooms appear in one branch. If you take the green path, you would need to backtrack through it, and eventually find a room with 3 doors on the other path (the only room besides the room before magic mirror room with 3 doors). If you went with the orange path, you would need to remember which was the room you passed with 3 doors, and go back there after finding the mirror.
Is it possible to determine that before wasting time?
Navigation Seals help with that a lot. Radars, compasses, and x-ray vision can help determine which path to take often from the start of the dungeon. Door Sense ability helps in figuring out those rooms with extra doors even if you cannot see the.
Then there is of course familiarizing yourself with templates (some room types appear on different templates, paths, and branches).
Of course if you would like to try to get better at the game, I would advise to play from the start, without using the cheat code, because harder templates appear on later days.
It's also better to exit dungeons before time runs out. You don't have to finish all objectives every run.
I am happy to answer your questions, even though I feel like I am spoiling a lot. What seals you unlock is random, but can be narrowed down by what seal types you need. Different playstyles come to play depending on your unlocks, and what templates you get e.g. navigation seals are very important on e.g. Maze template, but pretty useless on Snek template.