Co-founder of Levels.fyi here. We think about this problem space a lot in developing our own taxonomy: https://www.levels.fyi/t

One of the hardest things is that the same title (and level) can mean very different things across companies, industries and over time. When collecting pay information, we take great care to merge titles that mean the same thing while distinguishing those that don't. There's other edge cases like at some companies a title will be more specific (Security Engineer), while at others they'll retain the general title (Software Engineer) but specialize in the same thing (Security).

Claude has been really helpful in wrangling this all and expanding our taxonomy :)