This is what I do routinely as well. I am the final tier. Often when I get a problem, it’s been through three layers of helpdesk at two different vendors, two or three levels of sysadmin types, several tiers of developers, and frequently even more resources than that.

Many times, a team of 2-10+ people has been working the issue for weeks.

Most of those problems I solve in 20 minutes or less. When you’ve been doing the same sort of thing since 1980 and professionally for 25 years, you’ve seen a whole lot. And I just have a brain that is optimized for troubleshooting for some reason — probably because I have a great memory, accept nothing at face value from anyone, try things everyone “knows” cannot be the cause, and am relentless. These qualities take you very far in figuring shit out.