It's kinda funny how much alignment gets under everyone's skin for how minor a part it actually plays in the game. Mechanically, it's basically just a tag for a relatively small amount of spells and abilities to interact with. I think a lot of the issues come from treating alignment like a bigger deal than it actually is.

The designers want a Paladin's Smite to hit a demon harder than it hits an innocent. That makes sense intuitively to most people and a simple alignment grid serves that purpose pretty well. There are a lot of hypothetical weird edge cases (source: the thousands of pages us internet nerds have spent debating it) but they don't actually show up at the table very often.

You might disagree with that, you might remember some time your group got into an argument about a character's alignment, but did their alignment ever actually matter? I don't want to speak for everyone, but in my experience, the problems entirely consist of a character acting a certain way, some other characters, or the GM objecting to that behavior based on their alignment (or objecting to the alignment based on the behavior), then everyone argues a bunch. Eventually they settle on an alignment for the character, sometimes changing it, sometimes keeping it the same. Then that alignment never actually comes up in the rest of the campaign.

Alignment is a dumb, hyper-simplified mechanic, because its purpose is just to make a few abilities work a bit closer to what we expect (ie. protect evil should protect from skeletons). Most of the problems that arise from it come from people trying to use it for more than that.