Try small firms. You said you can't get B4 and (if I understood right) you can't get Top 20.
Hate to break it to you if you haven't realized this yet, but you're not a prime candidate. You have to realize that employment gaps make gaining employment challenging, and the CPA exams aren't a good enough excuse for 2 years off work, cause there's loads and loads of people who pass in half that time while working full-time (also loads of people who take much longer, but since there's many that pass, people aren't going to think “Oh, s/he passed exam May 2016, must have been studying full-time May 2014 – May 2016, and that's fully expected and normal”, cause there's decent odds the person reviewing your resume passed in a year while working or something like that).
Once you get a job and get into your career, then the CPA/MBA will propel you forward, so I'm not saying “you're screwed”. But I am saying that right now, for hunting a first job, you're not a prime candidate. You graduated 2 years ago and have 2 years unaccounted for except for something that the hiring manager may or may not view as a sufficient reason to be 2 years out of doing anything else.
So, I wouldn't target Big 4 or Top 20 or Top __ or anything like that in your spot; I'd target everyone. Target a small firm that rarely gets entry-level applicants who have passed exams, so would be happy to take the “risk” related to the employment history* cause it's rare they get the reward of an experience-pending CPA candidate. I'd suggest sending a stellar resume and cover letter to *every* CPA/accounting firm within the area that you'd be willing to work (driving distance assuming you don't want to move, or within the entire geographical area that you're willing to move to). I know of CPA firms here that the only CPAs are the partners. I'm in an area with a very low education level, but these are also very small firms. So, somewhere like that, if you came in with your exams passed and they knew you would be a CPA once you got a year of experience, you'd be something they'd never had in the time I've known the firm. Big 4/Top 20 regional, qualifications like yours are a dime a dozen, but in some small firms someone with a Master's and CPA exams passed would be a rare find that they'd be happy to take a risk for.
Personally a micro-firm is what jump-started my career. Pay was terrible (seriously), but this 1 owner & 1 full-time employee (me!) firm is where I was able to get a foot in the door (by dropping off – in person – resume and cover letter at every accounting firm within driving distance), then move to private accounting, and now 4 years later I'm the established Controller at a small private college. Small firms can get you started going to great places, whatever those places are you want to go (people also can go from small firms to bigger firms if big-firm accounting is your long-range goal).
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* It's not popular to say so, but it's a risk to hire someone with employment history concerns – currently unemployed for one reason or another. Some people who don't get a job for 2 years out of school are lazy and will be terrible workers; some are over-achievers who studied for the CPA exams in such a way that they will still know 99% of what they learned in 10 years. First one is bad; second one is good. Some are people who took a couple years to get the “kid” out of their system (travel freely etc.) or to have kids etc. and are new mature adults ready to settle down and dedicate themselves to a job; some have been unable to get a job cause everyone else saw something that you're missing that in 6 months you'll wish you'd seen. There's rare gems in the currently-unemployed-and-seeking market, but there's a lot of crap in that market, too. So, it's a risk when someone hires someone out of that market.