The family court system is broken, for sure, but it's the only system we've got. It sounds like you have good evidence to show a pattern. Definitely consult with an attorney, but don't put all your faith in them. I did the first time around- I thought I was dealing with a professional and that he would know what to do and do it. Big mistake! The most important advice I can give you is to never let any resentment show. None! Everything you do or say needs to come from a place of total compassion and genuine concern for your children's welfare. I look back on the first declaration I submitted to the court and I cannot believe my attorney didn't edit it. I was SEETHING and a lot of the "concerns" I listed didn't qualify as putting the kids in immediate harm. The courts have seen the worst of the worst, so a lot of concerns we have just seem like nit-picking to them. My ex had no trouble painting me as a vindictive ex-wife who only wanted to alienate him from his kids. Of course, I did have valid concerns, but they were overshadowed by my attitude.
It is possible that you won't be granted supervised visitation right away, but you have to keep your side of the street clean. By bringing the issues to the court's attention, you at least no longer risk having your rights terminated by CPS. Document everything and always communicate via text or email. Drug addicts are sloppy- even if your request for supervised visits is denied, he will eventually slip up.
I just found out today that the woman my ex-husband dated immediately after our separation- the woman who used to make my kids sleep on her bare floor, and the court's didn't give a crap- was arrested and is being tried for murder. She sold a guy heroin laced with fentanyl. Drug addicts are so incredibly dangerous. I really wish our court system was more realistic about the threat they pose to children.
But like I said, the truth comes out eventually. My ex has had supervised visits for almost 3 years now. It took a year of me petitioning the court for it, but here we are. The kids are safe. Do what you have to do for your kids.
Good luck