the simplest reasons for the delay are the most obvious: 1) ford was injured on set a few weeks ago, its gonna take months to rehab that. 2) Disney has a BUNCH of shit that has gotten rejiggered to not compete with DC, and there are only so many spots they want a big movie in. You don't need to bring in weird conspiracy theories or how Ford has been replaced by a lizard person and needs time to learn how to be human again.
Indiana Jones is still considered a summer blockbuster crown jewel, and putting it out in 2023 makes more sense (forcing other studios to move around it) than putting it out in an already crowded 2022 summer.
Remember, Fast and Furious, Top Gun, Mission Impossible, John Wick 4, Fantastic Beasts, Black Adam, etc already have staked 2022 summer spots. Then Disney moved into the summer Dr. Strange 2, Thor 4, Jurassic World 3, Black Panther 2, and a few more things. Its already shaping up to be one of the biggest summer movie years in history.
Most likely a couple MORE movies will be pushed to 2023, 2022 is already way, way, way too crowded. Its practically a new $200m movie every week which is unsustainable.