How do you live with the guilt?

I have a young rott (just turned 2 last week), we rescued him from a shelter at 10mths and he was aggressive to begin. Ive had rotts before and he started coming along with training both my own and professional, yesterday he bit me for the 2nd time hes tried 3 total, i have an elderly mother and 2 toddler nephews who I would like to have come over but hes extremely aggressive with food, toys, people that arent myself or my mother. We set the appointment after discussion with our vet, the trainers, and it just feels like a huge betrayal to him. Hes such a good dog 95% of the time and this is my boy, my older rott is more of moms dog, this one we do everything together. The trainer even was surprised how fast his temperament changes and told us bluntly that we were making a good decision and that hes just trapped in his own mind/world of anxiety and fear even though we have loved him and given him no reason to be afraid of us it was just ingrained so deeply that he couldnt be helped and we need to do what is the responsible thing.

Hes bit my mom a few times, snapped at my elderly neighbors, my friends, and family and no amount of socializing or special training has been successful and we have been doing it for over a year now… i know im preventing a severe incident where I couldnt be with him if he bit someone outside the household, or god forbid he attack the younger family members or my mom. But i just feel awful.

We thought about rehoming but the vet told us that a rott with a history of biting is not going to make it out of a shelter, and it would only endanger others plus raise his anxieties and lash outs.

How do I work through the guilt I feel? His appointment is on the 28th, gives me 2 weeks to love and play with him just like normal but i cry whenever we play because he looks at me and in his eyes I see the trust and love he has. The lady we rescued did nothing with him or for him just chained in a yard and forgotten so he didnt develop the brain wiring a typical pup would he had to become aggressive and protect himself and his items. But when he isnt “triggered” (idk what other word to use) hes a loving great boy. But he can flip without warning, no growls or intense staring or even body freezes he just hits the switch and when he calms down he knows he messed up.

I love this dog and I put everything into him, ive cried for 2 days straight now…i feel like both a failure and a fraud because how he looks at me and will still cuddle up with me and play and all the good stuff. But the threat to my family is greater than i can risk.

Sorry for the long post, but its a lot to carry and it feels a bit nice to write things out. And I said it a few times but i do truly love this dog with my whole being, ive poured my soul into him so dont think that this decision came easily (i know yall most likely wont but felt I should add it) it took a long time to get to this decision and it feels like losing a loved family member because he is.