Here's the first thing I'd do:
Move Whitlock back to the bullpen.
This isn't exactly scientific, but my theory is that while they started slow, their real slide started when Whitlock had to be moved to the rotation because Houk couldn't play in Toronto because he wouldn't get vaccinated. That denied the team their bullpen weapon and while the other guys were decent enough role players, pitchers like Robles got exposed in repeated high leverage situations. I can't really explain it but bullpen struggles have a way of infecting the rest of a team.
So fix that. It doesn’t solve the putrid offense problem and leaves something of a hole in the rotation. But using Whitlock's skillset more than once every five days will help slam the door situationally, put the other bullpen arms in better positions to succeed, and potentially have a larger effect on the team.