Could you please explain what you mean by ‘does not accept Monzo cards’?
There are several posts in the community where users have reported comparability with PayPal for some of their functionality, for example -
https://community.monzo.com/t/unable-to-add-monzo-card-to-paypal-wallet/6703
https://community.monzo.com/t/add-funds-via-paypal-balance/1059