My 6year old dog is potty-trained but still marks his territory around the house.. can I fix this habit?

I have a 6-year-old dog that was fixed around 1 year old. he is potty trained and never had issues with where to pee when he was younger (he had a pad inside the house that he did for poop and potty). A few years ago, we moved to a new house, and he suddenly started marking his territory everywhere, at first I thought it was a health issue, but everything with him was normal. We did give him some hempoil for anxiety, but it was 50% effective. Now we're moving to a new place, and I'm trying to prevent it from becoming like our last place. I talked to a trainer, and he recommended removing his pad and just making him go outside so he wouldn't get confused and that's what we did. he goes outside to potty 3-4 times a day, and he 100% knows that's where he should pee. But even though he's almost always supervised and not alone in the house, I noticed he marked his territory in 3 places already. (I don't even know when)

Here's my real question: Is this a habit that would ever go away? He used to have his freedom in where he goes inside the house, and he loves sleeping in my bed, but because I'm worried he would wake up and mark his teritorry I have to put him in a crate whenever I'm sleeping or need to go outside or even shower. I want him to be able to sleep next to me and have some freedom around the house without always being worried about him marking his territory but I'm not sure if that's possible..
If anyone has any similar experience or advice, I would really appreciate it!!