Well, it sounds like you are very resourceful and involved, and you've got a plan in place that you are executing. Your idea of wilderness and/or boarding school sounds like a good fit for your son.
My stepson is bipolar and while he isn't as antisocial as your son seems to be based on your description, he does display hyperactivity and impulse control behaviors that are somewhat similar to those you describe. Have you ever had him evaluated for mental illness? Sounds like you've focused on educational assessments, which is great, but if he has an underlying mental illness this will definitely exacerbate any learning or attention issues. The risk taking behavior, sneaking out of the house, etc. is definitely a symptom of bipolar disease in my stepson. It may or may not be for your child, but it's worth considering.
Do you know your son's biological history in terms of mental illness and/or personality disorders such as antisocial personality disorder? So many of these behavioral problems are inherited, it boggles the mind. And often these disorders begin to show themselves in early adolescence. For my stepson, it began with a suicide attempt this past September which was very nearly a completed suicide. He was 15 when this occurred and just recently turned 16, which is when he had his first episode of mania.
A certain degree of defiance and grossness is normal in an adolescent boy, but the chronic lying, illegal activities, sneaking out of the house and dealing vapes/obtaining money through possibly illicit means, etc is definitely not typical and I don't at all think you are overstating the situation.
Are you and his dad on the same page? That makes a huge difference in your ability to successfully deal with son's issues.
Unfortunately your son may need to live away from the family for some time, possibly months or years, if you are unwilling to continue living with the drama and chaos he creates (and i don' t blame you one bit, I'd make the same choice). The answers will come in time. In the short term others will chime in here to share their experience with wilderness programs.
Keep posting, we're here and we get it!