It has to be done similarly to how Casino Royale brought in a new Bond. Focus on a grittier action movie rather than the childish gags. Focus on the scenic escapism, shoot everything on location, and avoid overdoing the CGI. Robert Eggers would be a great director to bring in for that. He excels with period movies and historical authenticity. Put the story in 1930, 5 years before Temple of Doom, as Indy is just starting out as a professor at Princeton.