All payment processors collect basically the same exact fee amount.
Wix Payments
Square
Stripe
PayPal
etc etc etc
Even the banks do it.
It is the only money they make to process a physical payment for you. That is how they stay in business.
It is a business expense to you.
They charge a fee on the total amount being processed. You can’t charge a fake “tax” to recover a business expense. That is illegal. Speak to a local accountant about business expenses and your “tax” questions.
Some payment processors give you lower fees based on how much volume you produce over time. Other companies don’t take any fee at all, like Venmo or Zelle because they make their money somewhere else to stay in business.