Ko-fi doesn't display your email address publicly. At the payment stage, Ko-fi hands over to your own PayPal page for checkout, where the payment goes directly to your account. Ko-fi doesn't get in the middle of the transaction.
Depending on your PayPal setup, PayPal may show your PayPal email on their 'checkout' page.
It's possible to set up a new email account and associate that with your existing PayPal account. Your PayPal account can have multiple addresses associated with it.
Alternatively, you can switch your PayPal from a Personal account to to a Business account for free.
The name of your choice will appear on your payment page. This is the best option for hiding your email address from supporters.