I believe I know exactly how you feel, I made a massive mistake many years ago, that's not just the fault of red tape and bureaucracy and ignorance but also just me, but you can't beat yourself up about it even if at times that's difficult, you just have to eventually decide to move forward instead of dwelling.
I wish I could do something more substantial, but I hope you recognize the truth in what I wrote here, you're totally right with your last paragraph and it's an important thing to recognise.