> Big banks do not understand the cashflow situation of startups. They flag standard fundraising as fraud, drug money, or money laundering (or simply won't open an account in the first place).

It's not like they blacklist you the moment your attempt to open an account raises an eyebrow. Show up to BofA or Chase with a copy of your contract with your VC, in addition to their check, and it would be odd for them to refuse you an account.