"Quicken can only import qif files into empty documents.", whatever that means.
It means that the only way Quicken Mac can use a QIF file is to create a new Quicken Mac datafile; it can't be used to import batches of transactions.
I have a new "credit card" called "Amz_Mar-Aug_2022" -- not really what I wanted.
You can rename the account by Control-clicking on it and selecting Rename from the pop-up menu.
But I think the problem you'll have is that each time you import a Mint-format CSV file, it will create a new account in Quicken. You can select all the transactions and move them to an ongoing account, doing this after each import. Probably not what you're looking to do; just noting it is possible.
You're trying to do something Quicken Mac isn't designed to do. Quicken intentionally doesn't support importing CSV files because they aren't structured and would be prone to many problems. The Mint import was a one-off exception, and was desinged for a one-time import for people wanting to convert all their data from Minto to Quicken. You might consider purchasing a third-party software utility for converting CSV files into QFX which can be imported into Quicken, but since that's not supported by Quicken, we can't really discuss that further here.
CSV imports are always going to go into a new account; you'll have to drag & drop the transactions from that account to the account where they belong.
