I’ve used belly bands on some males. It won’t help with poop. If you free feed, stop. Feed him once or twice a day, so you can take him out after he eats. Put a leash on him in the house, so you can watch his behavior & catch him before he goes.
I’ve rescued a few different breeds, & poodles seem to be more resilient than a lot of breeds. They seem to get over abuse & neglect faster.
You might find a reward only trainer to help get him a little more socialized. Good luck with him. Thanks for sharing your life with a dog in need❤️

Have him checked for a urinary infection and then go right back to the beginning of potty training. When he wakes up, take him out. After playing for a few min, take him out. Right after he eats, take him out. Will he let you put a leash on him? If so let him wear it when you are there to supervise. If he does have an accident, quietly go and pick up the leash and take him outside. Lots of treats and praise for when he does what you want. I have a rescue that came to me when she was 10 months old. It took about a year and a half to get her potty trained! She is very "determined" as I say. She has been excellent for many years now! Good luck! It can be done!

poop [puːp] какать; какашки; ударить в пах
potty training - приучение к горшку