Losing my grasp of technicals as a brand new A1

Being good / technically proficient at your job once you're in the seat is completely different than knowing how to nail technicals in an interview setting, particularly if you're in a coverage or product group that isn't modelling intensive. I'd be concerned if you've forgotten fundamental accounting concepts i.e. cash impact of an increase/decrease in asset/liabilities or key components of working capital, but most of what we do isn't that challenging. Spreading comps and precedents, developing industry/company overview slides, and even more analytical content i.e. accretion/dilution, AVPs, etc really don't require much thought. In addition, most large institutions have pre-built templates so all you have to do is plug in a ticker and maybe swap in a few numbers. Unless you're working at a boutique or dealing with incompetent clients, you're never building a model from scratch either - you'll mostly be making tweaks / stress-testing / reformatting a pre-built corporate model.

I haven't used a pen and paper in >4 years in IB (aside from sketching slides and taking notes), and would probably be a trainwreck for questions involving complex mental math. I don't disagree that banking has likely made me less sharp from an academic perspective vs. years ago, but you develop other skillsets on the job that are much more valuable in the professional world. Especially if you're a coverage banker where your KPI is client relationships / revenue to the firm rather than just execution.