I recently upgraded to a Business Plan and have also been very confused by the lack of an obvious way to email Airtable with support enquiries. The approach I take is to use the "Message Support" button on the new Admin page for Business Plan users. When you've outlined your problem to a bot, you will get an email.
Now, the email you get will not answer your question. And it will be from donotreply@salesforce.com. Your heart will sink, remembering how Salesforce destroyed Heroku and forced you to migrate your stack. In fact, you will wonder if you are talking to a human at all or still the original chat-bot.
But if you reply to that email, it does go to a human at support@airtable.com. I've even asked if they are human and they have confirmed it. I'm not sure if that fairly passes the Turing Test, but it's a start. In fact, by some magic (or excellent impersonation skills), you will be talking to the same person in follow-ups.
Next comes the fun part, because you will be gaslit for 2-3 weeks until you get elevated to someone who hasn't just skimmed your question and copy-and-pasted links to ambiguous (and often incomplete) documentation. And they are very polite, very smart and will answer your question. I found that the only way to get elevated to them is to use humour and dark sarcasm. If you're funny enough, it will be shared within their call centre and someone who understands your issue may take over communication.
I haven't tried emailing support@airtable.com outside of a bot-initiated chat with an actual support number.
