There's no way for us to know how UKVI balances work flow without actually being employed there, and even then whistle-blowers are saying they are not giving any priority to spouse visas in favor of other more profitable visas that are easier to process.
See, for US applications, it can't be the case that they prioritise non-settlement visas because:
- Settlement visa applications (fiance, spouse, child dependant) are processed in Sheffield, UK
- ALL other visa applications (student, work, visitor etc.) are processed in New York City, USA
So, it is physically impossible for Sheffield to give priority to non-settlement US applications over US settlement applications without all the Sheffield staff abandoning their office and flying to New York.
As far as I am aware, Sheffield is a hub for settlement visas, while other visa type are usually processed at application centres in other countries.