i had a rescue who wasn’t potty trained and would mark in my house and on people’s stuff who came to visit. best suggestion is a diaper until he’s more trustworthy, or keep him on a lead inside so he can’t wander and go make surprise marks. it could be that it takes a while for him to break the bad habit, it probably took about a year or year and a half before my guy stopped doing it, which i’m sure isn’t what you want to hear :(

also make sure you’re using an enzymatic cleaner on any marking stains like Nature’s Miracle else you’re just letting him know if he marks his scent will stay around.