I want to invite you to consider that You are conflating Alignment and reputation.
That's the way that alignment was implemented in BG so that's understandable.
Alignment is an internal barometer of worldview that determines your ultimate place in the wheel cosmology after death. It can reflect in your actions and it can also change with experiences.
That's not innacurate but it's a flaw with 5e -- one of the reasons I'm warming up to Pathfinder. Don't get me wrong, 5e is still the best edition since 2nd but 5e's downplaying of alignment is one of its major flaws.
