Frankly, for me, the first cracks started to appear with the addition of Nardole. I just didn't click with the character. Reluctant heroes are one thing, but he actually came across as someone who just didn't want to be there, but for all the wrong reasons.
The scripts Whittaker got were, frankly, rubbish. Sorry. She really did what she could with it, but the heavy-handedness of the point they tried to make really didn't appeal to me. Doctor Who always had a pretty direct point, but it was handed with a lot of subtlety and care. And they managed to make you care, about the characters, about their fate and about the things they tried to accomplish, and that simply didn't work for me with the stories here.
I have pretty high hopes for Gatwa, though. He was brilliant in Sex Education and I hope he can carry that energy over. And PLEASE, give that guy better scripts!