if you have a zero balance -

add the debit card as one of your credit cards..
I’ve never done this, but you could try to send in payment format to yourself?
i.e. “send money,” put in your own email, the amount, and if you have 0 balance it might ask you from where you want to get the money from? or have that debit card as your primary source..

you can try that though I’m not sure if it’ll work..

or contact paypal and ask them?