Robust Technical Training

Are there any accessible programs that are robust in terms of technical training? I am talking at the level of Global Platinum Securities. I have heard these guys are often way ahead of the curve in comparison to their peers due to their intensive and comprehensive training. Currently a SA in the M&A group at a respectable MM bank. I broke into banking after transferring from a complete non-target. Grinded my way through off-cycle internships and gained tons of insight into working as a banker. I like to think I am one of the better interns and pretty proficient with Excel and PPT bc of the reps I got at other firms. The biggest problem I am facing comes in the form of challenging technical problems. I was allowed to work alongside an analyst and do a practice model of a pretty large cap company and was completely stumped. Yea I have modeled before, but the nuances of an operating model for a 1b+ company had me stumped and I realized how much I lacked fundamental knowledge.For some context, I am an economics major that has never taken a single corporate finance or an accounting class. I would prefer not to and do more of a self-guided studying. Anyone have any materials or know of any accessible programs that are comprehensive?Thanks.