Methinks you need to pay more attention to sourcing your ingredients….(synthesis route matters. As does competence in post synthesis clean up).
Decent amount?!?
I’d wager less than 2%? Probably less than 1%. Except for CBG, but that requires the right genetics.
You’re purchasing from a “hemp” lab , how do you imagine one gets from plants producing 10-15% CBD to 90+% CBN without chemical modification?
Define synthetic.
Maybe check out Search results for 'CBN SOP' - Future4200
Eg: CBC to CBN and Synthesis of CBN seems relevant.