Out of control teenager. Help!

Originally attempted to seek advice in r/Parenting, however my post was removed due to the smoking/drinking aspects.

40Y Old dad here. I hate to be consulting online strangers about this, but I’m utterly lost and quite honestly at my breaking point with my son and everything he does. I feel as if I’ve exhausted every route I can conjure up and nothing is working, nor are professionals I’ve consulted, so this is my last ditch attempt of grasping at straws trying to find something that does help. I figured I might get some advice that better aligns with my values and morals from other gay parents.

My son is seventeen. I’m a single father, but he is biologically my child. His mother is not in the picture and hasn’t been since he was two. I feel the need to forefront this request for advice on behavioral correction by making it clear that I’ve sought professional help already regarding this situation. My son has seen numerous counselors, therapists, psychiatrists, and other doctors and general child/teen behavioral specialists. It’s been pretty damn solidly determined there’s no underlying mental illnesses, hormone imbalances, or environmental factors contributing to his behavior. As much as I hate to say it, I truly believe he’s just a badly behaved kid.

He hasn’t always been a nightmare, growing up he was the sweetest kid until about a year ago when things slowly went downhill. He went from being well behaved at school and home, hanging out with good people, being active at school and socially, to now the complete opposite. No major life events or changes occurred that I know of. It’s been a slow but steady behavioral decline. He has zero respect for me or any other source of authority, zero comprehension of or care for repercussions, zero impulse control, and overall is horribly behaved. I quite literally can’t possibly even begin to list all of the things he’s done this past year or so, but to paint a picture some notable behavioral choices he’s made are him:

-Disappearing for nights/days at a time with no warning or explanation. -Drinking/Smoking (Neither of which I even keep in the home). -Stealing my car (He has/had his own, but I’ve had to start taking his keys and removing his license plate due to how he acts. In response he started to take mine, so now I have to hide my keys as well). -Disappearing for two days only to pop up two states away from home. (No, I didn’t report him as a runaway because of how common his habit of just leaving and not telling me is. I also wasn’t aware he was in another state). -Underage sleeping with people my age -Acting out at school and showcasing a lack of respect for teachers (Numerous counts of Saturday school and detention. Ironically he still has good grades.. somehow). -Refusing to go to school (He’s racked up countless absences and is indifferent to school-assigned disciplinary action). -Cussing me out -Regularly getting in fights

I’m ashamed to say that’s not even the tip of the ice berg, but I’d be typing all day if I listed everything. The point is that he’s wildly. out. of. control. I feel like I’ve exhausted every single discipline and behavioral correction method I can. I’ve tried taking away virtually everything, putting a lock on his window, installing cameras in the driveway, grounding him (Not that it ever works. I’ll leave for work and he’ll walk out the front door right past the cameras with zero fucks given), taking his keys/license plate/car, making him take drug tests/do breathalyzers, having friends in law enforcement have talks with him; everything. I refuse to hit or physically harm him in any way as much as I admittedly loose my temper at times. I do yell at him, but that clearly has little effect. Words don’t work on him and it only ever ends in screaming matches between us. I refuse to send him to one of those wilderness camps. I’ve heard enough horror stories from them. Boarding school is on the table, but I’m honestly terrified of how he’ll act fully outside my supervision and I’d never forgive myself if something happened to him.

Most people I’ve spoken to say he’d be a good candidate for the military, but I’m pretty sure I can’t just.. sign him up for the military.

Needless to say, I’m at a loss. Please, I’ll take any advice at this rate. Discipline ideas, potential boarding school advice, other medical/psychiatric areas worth looking into (though I feel I’ve exhausted all of those), ways I can support him through a more gentle parenting approach, anything. SOS.