Help with accepting a job offer

Hi, this is my first post here, so sorry if I have placed this in the wrong place.

I recently graduated with a 2:1 from a top UK university in economics and economic history. I previously interned at two boutique asset management firms the previous two summers, and I have just moved to the US as my wife lives here. I am interested in investment management, as well as equity research as I enjoy following the markets, and I enjoy researching stocks.

However, I did not secure a graduate offer, predominantly because I didn't know whether I would be living in the UK or the US post-university. I have recently been applying to jobs all over the financial industry, as I need to get a job, although my overall goal is to get into the industries mentioned above. A 3rd party recruiter contacted me last week and asked if she could submit my resume to a BB bank. I accepted and I interviewed with them today, for a back office operation role. They offered me the job this afternoon. I am not particularly interested in the role, however it is a job with a reputable bank. I am however worried that this will prevent me from getting future jobs in the area that I want to be in. However, I can continue to apply to jobs whilst working there, and I can view this job as a stepping stone until I finds something that I want to pursue.

What should I do? Do I take it to earn some extra money whilst looking for other jobs elsewhere, or do I pass on this opportunity and focus solely on job hunting. Thanks for your help!