Of course I understand how it works. I just can't constantly keep in mind what garbage I played around with 3 months ago that might be responsible for the issue

Of course I understand how it works. I just can't constantly keep in mind what garbage I played around with 3 months ago that might be responsible for the issue I'm looking at right now. I don't expect it, and more importantly, I shouldn't have to expect it. It's a basic tenant of development. Eliminate all additional sources of issues and complexity by presenting a clean, well-controlled sandbox in order to effectively diagnose it and fix the real bug. In fact, you should be able to try a newer version of a dependency, an older one, or run 10 variants (containers) each with different versions to e.g. test whether the project you're working on is widely compatible with a flexible range of that dependency. These things are done all the time. The tools are inadequate, not the developers. Engineers on both sides need to stop assuming everyone else is an idiot.