I think worrying about what comes next is a fools errand. The characters are timeless. Make a land based around them in some sort of timeless form and that’s enough.
Look at MSHI. Sure it’s not the hip version of the characters we currently see in film, but at the same time it’s a timeless version of those characters that won’t feel horribly dated once the MCU’s time passes
Great point!
Sorry to take this off-topic a bit, but I don't think the MCU will ever get outdated. It's probably going to end up like Harry Potter.