This is a review done by my sister (we aren't British, Scottish or else so enjoy but don't care about the mistakes) :

I've seen the Christmas Special with my brother. While we're both fans, he is way more invested than me - he's seen every episode, while I tend to watch them in random order (keep your tomatoes!). With two such perspectives, we thought, we would both enjoy the Christmas Special.
It left us a weird taste in the mouth. I'm not saying this episode is bad, but it's not good either - it's meh.
Starting with the good points : as always, Ncuti Gatwa's excellent acting. This man could play in a Hallmark movie and make it convincing and heartwrecking. I loved the beginning! The idea of the Doctor bursting in and out of various locations to offer a pumpkin latte and a grilled cheese toast - lovely. The Time Hotel, too, was a really fun concept, and the shots inside were lovely and whimsical in the best ways - I'm talking about the first shots, when both viewer and Doctor discover the inlay of the Hotel. I also enjoyed the relationship between Anita and the Doctor, the mundane really works here. Although I would have preferred that the relationship weren't romantically coded. It doesn't really fits either character. Coughlan plays pretty well, all things considered (see part two of review), and her quick wit and chemistry with the Doctor are simply delightful. And there is a dinosaur. What, do we seem to be asking ourselves, could we possibly ask for more?
While the episode does have great concepts (see: Time Hotel), it doesn't seem to exploit them as well as it should. Coughlan does play her character with talent, but said character isn't deep enough. She turns into a star, alright, but it doesn't feel natural. Her backstory with her mother, while sad, and significant (Doctor Who episodes are allowed to make references to actuality and I've missed any COVID presence in recent fiction), doesn't feel complete. Especially the ending, in which the mother becomes part of the star: very meh, and a bit too "don't worry magical sci-fi saves us all". I, for one, would have preferred to see the Doctor coming, or someone keeping her company. And the Christian end feels placated (a consequence of Disney buying DW, or my own religious issues talking?). The Anita storyline is by far the most significant and endearing but is spoilt by the romantic themes associated - it thrives in the mundane, not the romantic love.
In short (the conclusion we reached together while debriefing the episode), it feels like it could have been two episodes to allow both storylines to develop. While it is an important episode for the Doctor's development, it does feel like nobody really knows where to take this new Doctor, and it shows. The line on the armchairs is pretty wonderful, all things considered ; the moping on Ruby isn't. While I love Ruby Sunday with all my heart, her presence in the episode felt a little placated (if that's the word I want) and the Doctor's issues are just weird. I may be stupid but I don't get why he left and didn't bother coming back sometimes to have coffee with her. While I love both of them and their duo, they tend to steal the spotlight anyway - which is why we're coming back to the Star Seed plot. Nice concept, a return of Villengard (corporate greed at its finest) and definitely not enough screentime for Coughlan who could have shown her acting range had she have been given the opportunity. Joy's outburst: yes. Her becoming a big ball of gas on fire: no. She feels a lot like a mean to an end.

Points given to side characters: Trev's delightful. I love him. His determination to do good and not fail the Doctor (and isn't that a gimmick that will haunt the Doctor) is lovely and endearing. And the lady in the Orient Express, too, despite her short amount of screen time, feels right.

What I expect from a Doctor Who Christmas Special is to make me dream, throw my fist in the air and scream - this one didn't. The concepts in it feel underexploited as a plot part, overexploited as a part of Doctor Who. Again, Joy's too shallow a character to allow the viewer to feel for her (might be my heart of stone though) and feels drowned in the chaos that is the episode, as it doesn't seem to know what it's aiming for and where it's going.
All in all a six out of ten for the acting and the cosy ambiance of it, but its numerous flaws.