Like cmon its not that hard

Wasn't there some time travel/alternate dimension episode centered around Candice and how the boys being caught caused some terrible stuff/future to happen?
May be misremembering but I feel like that was a plot at some point.

There's two episodes I can recall in which the boys get busted. The first is Season 1 Episode 45 which results is Phineas and Ferb being sent to military school. This is eventually revealed to be a dream sequence.
https://phineasandferb.fandom.com/wiki/Phineas_and_Ferb_Get_Busted!
The second is Season 2 Episode 25 in which time travel shenanigans lead to Doofenschmirtz ruling the future and fun/creativity being banned by parents.
https://phineasandferb.fandom.com/wiki/Phineas_and_Ferb%27s_Quantum_Boogaloo