It's all about the investment. Remember they paid BILLIONS for Lucasfilm, Star Wars and Indiana Jones. There's a big difference there in terms of the IP and what the ceiling is from, say, BATGIRL. Even a mediocre Indy movie has the potential to at least do "okay" and keep the franchise alive, enough to do their Disney+ series and however else they want to exploit the IP's value. Disney didn't buy all this stuff not to remake and regurgitate it over and over again -- as well they've already shown us.
Doomcock says the movie ISN'T going to be saved -- it's too late for that -- it's just minimizing the damage, shuffling around scenes it sounds like to remove Waller-Bridge from large sections of the movie. He also says her delivery of lines was a problem -- what was "meant to be like Princess Leia" sarcasm instead became leering, unappealing snarkiness. The audience HATED it, just like how they were going to end the film. (Of course we should argue WHY she was ever cast to begin with -- another Kathleen Kennedy special!).
One thing's for sure -- Williams' score is almost certain to be a mess. Even rescoring the ending won't help the rest of it, which undoubtedly has been re-edited and re-shot so many times from when he initially scored it that it'll be a patchwork at best.