If we just stick to Indy himself, he's almost completely shorn of everything that made him cool. He's a drunk, getting divorced, lost his son, now working at a cramped school, hates his job (his passion, archaeology), hates his students who show him no respect, and has no interest in anybody or anyone, almost all his friends and family have left him or are dead. That's not even going into the fact that he's slow, old and can no longer believably fight. This state of affairs doesn't change by the time Indy decides to die in the past.
We find out later in probably the nicest scene in the film as to why he's depressed - Mutt was killed in the Vietnam War, which he'd joined to spite Indy - but this makes no sense. Mutt was a greaser, a rebel and anti-authoritarian in every sense and resented his father - who was a decorated veteran and a patriot. How the hell would Indiana 'I Like Ike' Jones unintentionally convince his rebellious authority-adverse son to join the army? It also damages Marion, since it's implies she left because of his depression and guilt over losing Mutt. Talk about kicking the dog when it's down.
We also find out Indy realised Basil Shaw was becoming obsessed with the Antikythera piece, and Shaw realises how dangerous it is and begs Indy to destroy it. Indy looks him in the eye and promises...then doesn't. He keeps it at the university, which means the only reason anything is happening and why people are dying is because Indiana Jones betrayed a close friend who turns out to be right, and ultimately abandons Helena.
Indy is barely a protagonist because his actions are entirely lead by everyone. He's constantly outwitted, outshone and overpowered. It's Helena who visits him, then steals the half of the Antikythera, then abandons him to sell it in Tangiers, does the majority of the physical action during the zany tuk-tuk chase and remembers the bulk of the information of her father's notebook. It's Sallah who saves him from a randy who was about to expose him for being a murder suspect. Indy hires a boat, but the crew are all killed by the Nazis (more dead friends), and it's Helena who bails them out by realizing the grafikos has a hidden message, and then throwing some dynamite. Indy gives Voller the Dial piece after he threatens Helena (this is done much better in The Last Crusade because Donovan actually shoots Henry Sr., and getting the Grail was the only way to save him), then gets shot himself.
Teddy then rescues them from the Nazis in the Tomb of Archimedes and assists Helena in rescuing Indy by flying a plane despite never having flown anything before. The Romans shoot down the Nazi's plane that kills Voller and the Nazis. Finally, Indy irresponsibly begs to be allowed to die in the past, and Helena Shaw somehow knocks him out for days with a single punch, drags him back into 1969, fixes his bullet wound, fixes his marriage, finds Sallah (who she's never met) and presumably clears him of being a murder suspect.
I honestly don't mind Phoebe Waller-Bridge, but she's not an action hero, and she doesn't have the gravitas necessary for this kind of role, and the smug know-it-all way she plays Helena made me think the big reveal of the film would be that she herself was a time traveller from 2024 come to 1969. In the age of Angelia Jolie's Tomb Raider, I would be quite happy if Harrison could hand over the role to a woman, but I can't think of anybody now who could do it.
