Soldato
From all the various rumours on SM (and therefore 100% accurate ) one possibility is that the director specifically didn't want another Joker film to be made, so when the studio pressured him, rather than passing on it and it being made by someone else, he's deliberately "poisoned the well" with this film, ensuring the franchise dies here and now.
No idea how true that is, buts its an interesting think to consider, almost cutting your nose off to spite your face etc as this film has hurt any further career he had I'd say.
It does sound conspiracy theory-esque, but I find it believable. It reminds me of a nightclub I went to in late 2022 with perfectly ample security but got closed down a fortnight later due to inadequate security which allowed a fatality (stabbing) to happen. My belief is that the local council killjoys didn't want this place open in the first place and ordered someone with inside tracks to manage the club that night and torpedo it. Different motive to the Joker but this is what it reminded me of.