apple says account recovery will take days - can i speed it up?

if you set up a recovery key or a recovery contact at some point, use that instead, it skips the waiting period. if you're not sure whether you did, it's worth a look before sitting out the days.

No, support can't shorten it. It's deliberate so someone who stole your phone can't take the account over quickly. What you can do is avoid making it longer. Don't keep starting new requests, and don't use other devices that are still signed in to that Apple ID while it's waiting, that can cancel it. But check this first: if any device is still signed in (an iPad, a Mac, even an old iPhone in a drawer) you can usually reset the password straight from its settings and skip recovery completely.