Omg I am in the same boat you are!! I have a 4 yo male and I am at wits end just like you!!! Honestly I just started from stage 1 all over again! He only has the half of the house so I can watch him. I watch him and take him out about every 1/2 hour. During the day when I am at work he is in his pack n play. ( he will hold his pee and poo while in there) I give him a little water and some food just in case.
At night he is in his crate to sleep.
That is how I am doing it, honestly you just have to watch Zip 24/7 like he is a puppy! Yesterday went wonderful, we had no accidents! There will be good and bad days, just try to watch him and take him out to go pee and poo and treat him when he does.
Hang in there!! It will get better, I HOPE!