Will an LLM from the external University of London help me get admitted to a top JD program or in any way help my job prospects out of law school? (especially if I want to work for a UK firm in London, Hong Kong, Singapore, and speak Korean, etc.)?

I have a 3.94 GPA and a 172 LSAT, but I was poor and broke after college so I went to Officer Candidate School and enlisted in the US Army for 3 years to get GI Bill money for law school.

Eventually, I want to go to the best US law school I can get into. My numbers are high enough to give me a shot at the top 10, but many people with my numbers get rejected at Harvard, Columbia, NYU, Chicago, etc.

I've heard graduate work can improve one's chances of admission, and I have tuition assistance I can use for distance learning.

I'm looking at an LLM in Corporate and Securities Law from UoL or a Postgraduate Diploma in Banking or Economics (given what I want to do, both could have merit and I'd have to study them more carefully to decide) through the external London School of Economics (LSE).

I've heard BigLaw employers (both US and UK) don't have much use for LLM's and instead prefer graduate work in a discipline relevant to the legal practice, such as Banking. On the other hand, doing an LLM now could show initiative and a long standing interest in law, and perhaps an aptitude if I achieved it with merit (something that might be more challenging in a quantitative subject, for me).

Which degree am I better off doing?