Differences in Drug Formularies & Insurance Plans

I (23f), US based, am currently on my parents’ insurance plan (BCBS) as an out-of-state dependent. I live in MA, and my parents’ live in TX, so my plan is BCBS TX out-of-state.

I have a severe chronic condition (non-psychiatric) and need a lot of the newer, more expensive brand name drugs to manage it. My current plan will not cover these medications. They’re on the formulary as far as I can tell (have read the most recent formulary + full policy for BCBS TX multiple times) but the prior authorization keeps being denied with no explanation as to why specifically. Additionally, my physician said that when the pharmacist ran the PAs for these medications, the insurance either a) denied w/o explanation or b) said the med was excluded from the formulary (despite the most recent formulary saying otherwise).

Not sure why it ran differently for the pharmacist than what was found on the BCBS TX/Optum RX websites. I absolutely don’t understand the “tier” stuff or how individual plans impact tiers. Multiple different physicians (PCP, multiple specialists across two related specialities to this condition, ER docs, and two different hospital systems) have tried to push forward the PA for these meds for me with no success. Cannot find anyone in the insurance company who will tell me the reason for denial, even upon appeal (multiple appeals + new PAs have been sent, like every month for the past year).

I’ve tried all of the generic or more standard drugs used to treat this condition, and they didn’t do anything for me. I work full-time and was recently offered a BCBS MA standard HMO plan by my employer (got offered new job).

I can’t decide if I should opt-in or not. I know it’s hard to say without more specific info, but in general:

Do formularies vary by state, even under the same provider (TX v MA)? Do they also vary by plan within the same provider (HMO v PPO, in-state v out)? Can having a primary & secondary insurance help increase my coverage? Ex: if I need A covered, primary covers 10%, secondary covers 10%, does this mean my total coverage for A is 20%?

I don’t want to opt-in and pay $200-300/mo for BCBS MA if they’re still going to deny the same meds.

Is it possible to buy supplemental insurance to help with prescription drugs only? I don’t think I qualify for Medicaid, and doubt Medicaid’s prescription drug option would cover these if I did.

What are my options here? Insurance company, my providers, pharmacists, parents, and anyone else I can think of asking (including Google) haven’t been helpful. Do I need to consult a lawyer, social worker, patient advocate, etc?

Any insight is greatly appreciated.