I'm a very, very casual Doctor Who watcher and for me, the season finale didn't really live up to the universe shattering revelations it was selling IMO. Granted, my lack of knowledge for Doctor Who lore means that the whole business about The Doctor being the Timeless Child meant little to me. I don't see how it upends Jodie's Doctor's world in particular. Yes, she has been lied to. Her memories altered perhaps, but that doesn't seem that big a deal for a time traveling alien that has lived multiple lifetimes already. I was glad that the Master did say that he hated that the Doctor being the progenitor of their species meant that there was a part of her inside him and that what he hated because up until that point I didn't understand why the Timeless Child/Children hidden history necessitated wiping out Gallifrey. I chalk up The Master's reaction to his insanity and ego, and his love-hate relationship with the Doctor. It felt like this Master was a Clown Prince of Crime-like incarnation of the character IMO.
I thought the first half of the episode was the strongest. I liked the fast pacing and the production values. I really enjoyed the Cybermen and their leader, who reminded me of Ultron. Once the episode went into the Timeless Child/Children history it started losing steam for me, and I didn't care much for the Master's ultimate plan which felt ho hum. It wasn't much different than the Ultron-Cyberman's plan. I did like the Timelord-Cybermen though. Unfortunately they were too easily defeated. This storyline could've been resolved in next season's opener. I don't think this episode pushed hard enough or really turned Doctor Who history and lore on its ear.
I was happy to see the Ruth Doctor again, but I wished we had actually learned more about her history and how she fits into things.
Going into it, I was expecting some major character death, but the one we got wasn't surprising. The cliffhanger we did get does bring back the Judoon but it felt anticlimatic. Ending the season with the Jodie Doctor about to kill herself, the Master, and the Timelord-Cybermen would've been better.
Time lord Cybermen are a rubbish thing anyway. Cybermen already take over dead humanoids, and can already time travel. I am just surprised the cyberium wasn’t outed as validium. Time lord tech. Just something else borrowed from past episodes in the bad collage we call who these days.