The thing that's good about the grandmapocalypse is popping the wrinklers for their cookies but not much else (at least what i think). You can always just turn it off, it's not a big thing and you can turn it back on any time. Later into the game there's some other things related to the apocalypse, mainly the seasons and season switcher, so don't forget about it just yet.
Tdlr: if you want to stop it just do it you can always turn it back on again
Yes as I said, do as you please with it. At your point in the game the trillions of cookies it costs no longer matters much anymore so it's more like clicking a button. No need to overthink it. Just do it if you want to.
If you spend more time afking on cookie clicker Grandmapocalypse is amazing but if you are one of those players that actively interacts with the game very often it may not be as productive to you. Personally I just leave cookie clicker open in a tab open and while I do other things, couple this with the golden switch for a 50% cps boost and then pop the wrinklers after switching Skruuia into diamond slot then putting whatever was in the diamond slot originally back into it I can get a lot of cookies for doing literally nothing. Overall Grandmapocalypse is one of those in game event type scenarios that tailors more to the AFK player than the gotta click dat cookie as fast as possible player.