I’m not quite sure if I meet your qualifications for a “hardcore” flashlight reviewer - I rarely do beamshots, don’t have a calibrated way to measure output or throw, and a lot of what I do is just sharing my opinions.
All that being said, I review lights often enough that I started up a website dedicated to reviews. Just like anything in life, having a workflow helps cut down on the time cost. I’ve done it often enough that I have a template for my headings and I know what measurements and photos I need and want to take.
Of course this hobby takes time, but I would spend a few hours a week browsing the forums otherwise. I’d rather use those hours taking measurements and learning more about DC electronics and test methods. As an engineer by schooling, those things interest me. It also helps keep my spending on the hobby in check, since something I’m excited for is always in the mail.