Someone told me a business PayPal can’t refund unless I send money first. That sounds strange — is that a real rule?

No, you do not need to send money before a business PayPal account can send you money back. If you are expecting a refund or payment, the business can transfer the money directly to your PayPal account without requiring any additional payment from you first.
For refunds of a completed payment, you can simply contact the business or seller to request the refund. They can process it directly through their PayPal account.
Be cautious of scams where someone might ask you to send money before receiving a payment or refund. PayPal does not require such a step for legitimate transactions.
Learn how to get a PayPal business account from the unsupported countries:
https://businessglobalizer.com/blog/how-to-get-a-business-paypal-account-from-not-allowed-country/