I’d be fired if that happened without a reasonable explanation why I was so terrible at the task I took on and let my team down by taking that long

I know it's easy internet points to say we should have accurate estimates, but that's not an actionable comment. That's like saying "cars should be safer" and expecting applause.

Most clients would rather you just give an estimate with 15 minutes of eyeballing it and hold you to that. That's not realistic, and it's not on developers.