I defo agree with the posts about the weird dynamic between Carrie and Lydia.
Even though Lydia is obviously more well off than Carrie, she is clearly jealous that Carrie has her own life, friends, had a career at some point, and has her own sense of style etc. Remember the vlog where Lydia went over to 'help' Carrie decorate the tree and all the backhanded comments she was making about her house and decor. IMO that's a clear sign of jealousy. Carrie has quite clearly bettered herself over lockdown (look at those arms!!) and had some life experiences. For whatever reason she's now selling her house which indicates she's in a good financial position to buy another (doubt it's because of what Lydia pays her but more likely she's a savvy saver and is now making use of no stamp duty till March, etc).
Carrie knows she enables Lydia and thrives off it, and this makes Lydia more and more needy. The more I think about it the more I feel Carrie is a ticking time bomb. In the sense she's doing as much for Lyds as she can so she can put experience of working with lots of well-known brands on her CV, building lots of contacts... and planning her escape to a better career. In the meantime though why not make the most of all the freebies while she can! She's a wily one I reckon...and tbh why not. Surely Lydia can't have expected Carrie to be her servant for the next 20 odd years or more!