What if The Hobbit was made into the first few films in Lord of the Rings instead of its own thing?
I’ve come across one pair of editors on Reddit attempting to do that. Before then, I’d toyed with it myself, but thought the time skip would be too big of a problem. Then it hit me (well, weeks later); just use the otherwise useless framing device of old Bilbo writing the story! That way there’s technically no time jump, it’s just the first two films are flashbacks.
Building off of that, how about a Rashomon/The Last Jedi style contradictory tellings of Riddles in the Dark? When Tolkien first wrote The Hobbit, Bilbo wins the riddle contest legitimately and Gollum is willing to give him the Ring (although he can’t find it because Bilbo already has it). When he started writing Lord of the Rings and realized that portrayal of Gollum didn’t match his new story, he rewrote the chapter for new editions and decided that the original was a lie told by Bilbo. Thus, in the first film, when Bilbo meets Gollum, the events could play out like in the first edition of the book, since we’re only seeing this through the perspective Bilbo gives us. Then, in Fellowship of the Ring, Gandalf tells us the true story, which he has deduced from speaking to Gollum.