How does a health insurance plan relate to prescription plans when all plans use the same prescription company?

My husband's employer offers 4 healthcare plans. A, B & C through Aetna or D is Surest/UHC.

All are paired with Express Scripts. We are currently on plan A (but in 2024 it was UHC not Aetna) also with express scripts.

The express scripts plans are all the same, but I'm wondering what the effect of the different healthcare plan options have on Express Scripts coverage (as far as prior authorization for certain medications) who makes those decisions? The health insurance or the prescription company?

Considering Surest because we've only ever been on copay plans prior to this year and didn't love being on a coinsurance driven plan (we hit deductibles but are no where near hitting OOP max). I'm just concerned because some of our medications required prior authorization and I don't know if Surest will make that harder. Surest is about $1,500 less per year.

Thanks!

|| || | |Option A Coinsurance|Option B Coinsurance|Option C High Deductible|Option D Copay| |Deductible|$600|$1,200|$2,300|$0| |Preventive Care|$0|$0|$0|$0| |Office Visit (including virtual care)|20%after deductible|20%after deductible|20%after deductible|$10 to $75copay| |Hospital Services (including imaging)|20%after deductible|20%after deductible|20%after deductible|$75 to $2,500copay| |Urgent Care|20%after deductible|20%after deductible|20%after deductible|$50copay| |Emergency Room|20%after deductible|20%after deductible|20%after deductible|$500copay| |Maternity Care and Fertility Coverage|20%after deductible|20%after deductible|20%after deductible|$100 to $1,600copay| |Out-of-Pocket Maximum|$2,000|$3,000|$5,500|$3,500|