Puppy going inside at 10 months old

I feel like I come here every month to try and find solutions. My pup is a maltipoo, 10 months and a week old now. He is still going inside to THIS day. Mostly just in his playpen. It has gotten alot better, like from a couple months ago when he would go after every hours or so. To having days of him not going inside. Whenever he is in his playpen, he will go after an hour, wether we are right beside him watching him until he wakes up, or if we are doing our work and have to put him in his playpen because we cannot look over him. He has been doing this since he was a little pup, but when we are not at home, he will NOT go until we come back home. Interms of him giving us a sign to need to go, he does not give us one. Well its one sniff and boom, just goes right there. We are getting him neurered in about 2 weeks, as our vet and groomer said thay its possible that its just him marking territories. We live on an upper unit, and have a little patio area that he uses with a “realistic” grass patch, the reason why we dont take him downstairs is because he will ring the doorbell that we have set up every 5 minutes or so, and no one wants to keep on bringing him down just so he doesnt even do anything. He knows that he needs to go outside, as whenever he is not in his playpen, he will go outside to do his business. My question is that when he gets neutered, will most if these behaviours go away? With of course more training that i get from my pet trainer. And how long did your pups take until fully potty trained?