Okay, in the late 1970s, there WAS a really bad movie ABOUT this called “Americathon”, a great concept that bombed in every way possible, and around the same time, there was a movie where Julie Andrews had a brief topless scene. The MAD treatment of said movie had two crew members say, “The writer figured that if they showed Julie Andrews topless, it would make enough money to break even.” Another one replies, “If it showed Dolly Parton topless, it would make enough money to pay off the national debt!”
So, FWIW, these ideas have been tried. I know that “Titanic” and the “Avatar” movies came close (sort of).
Continuing that line of thought, the obvious choice is a remake of Avatar where Jake and Neytiri have graphic sex while on the Titanic. Since James Cameron directed and wrote both films, it should be a breeze for him to merge the storylines.
A teleporter accident causes the Justice League and Avengers to accidentally be sent to the same alternative dimension world where all their villains now rule the Earth.
Ethan Hunt (Tom Cruise) of the IMF is sent on his most difficult assignment yet, tracking down a former Mi6 Agent who faked his own death and is now in hiding. Upon finding him Hunt is shocked to find out it’s actually James Bond (Daniel Craig) and not only that, he also has to deal with a couple of former Agents played by Pierce Brosnan and Timothy Dalton.
Figuring 1000 screens: all those things above, $2K per ticket and a two popcorn and coke minimum at an only slightly higher price of $2K each and it would be nice if you’re leave a couple grand on your seat before you leave to pay the actors & production company,
Before I even read the OP I was thinking “sex sells”. You basically get every (legally) young, attractive celebrity possible nude on-screen. Basically The Fappening: The Motion Picture. Plot is entirely optional. Possibly you could get something from a parody of Cats called “Twats”.
The problem with that - assuming that you mean in-theater - is that a lot of people find it awkward to watch sex when there are people alongside of them. It doesn’t stop many folks from still watching pornographic films in theater, regardless, of course, but I think for a truly Fappening movie to make the maximum bank it could, it would have to get its revenue from people watching it in private at home.
To answer the OP: I’ve always felt that a movie about the world operating by Biblical logic would make bank, thus showing the absurdity of the Bible while also sparking a lot of curiosity among Christian viewers. For instance, a movie titled “If God Were Real” and it shows San Francisco being destroyed by fire and sulfur from Heaven for being too LGBT, the English Channel divided in two so people can walk across on dry land, the angel of death smiting 186,000 Russian soldiers in Ukraine in one night, Christians drinking cyanide and being unharmed, etc.
Closer to a sure thing: IMAX remake of whatever ‘girls in love’ movie (indie? outright porno?) was already most financially successful—but this time starring Taylor and Beyoncé.
Add a car chase and a no-holds-barred fistfight between Timothee Chalamet, Dwayne Johnson, and Jason Statham, and you’ve not only paid off the US national debt, but provided enough left over to pay for a carton of eggs and Belgium.