Chances of getting TS SCI w/poly after being unsuitable for public trust?

I was given an unsuitability determination for a position of public trust almost 2 years ago now. This was due to admitted marijuana usage 6 months prior. I haven’t used since and my record is clean otherwise, to my knowledge. I have the potential opportunity to move to another project in my company supporting the intel community, which would of course require a TS with polygraph. Although my previous determination is multiple years in the past now, what are my chances with this level of clearance? I’ve heard intel clearances are notoriously difficult to get and I’ll already have this mark on my record. What about lower level clearances?

I’ve been able to support a project within my company that does not require any level of formal OPM BI, but I know I can’t stay where I am forever and I feel like I’ve got to get cleared in some way if I’m going to invest in this career path any further. That is to say, if an opportunity arises to move projects within my company and get some form of clearance, I’d like to be as strategic as possible. Any and all insight is appreciated.