Having worked at both a mid-size EdTech company and now in a smallish part of Microsoft, every codebase for public-facing software that I've seen would take at

Having worked at both a mid-size EdTech company and now in a smallish part of Microsoft, every codebase for public-facing software that I've seen would take at least 1 year to achieve actual expertise in (while guided by an expert!) and would probably take much longer.