I became a US citizen in 2021 and changed my name back to my maiden name. I still have a United Kingdom passport that does not expire until 2027, but it is in my married name. Can I enter the UK with my UK passport?
Yes. Just because you have completed a name change in the US this has no effect on the validity of your UK passport. However, in general the UK does require the names on passports for multiple citizens to be aligned. When you make a future passport application you may be asked to submit a copy of your US passport and in this case, it's likely they will only issue your UK passport to match this (or they may add an observation to the passport regarding your US passport, if not).