Using only one payment provider, either Stripe or PayPal, can be a good choice to improve your marketplace's focus and simplify things a bit. If both Stripe and PayPal have been enabled, you can also decide to disable one of them.
How to disable a payment gateway, Stripe or PayPal
Log in your marketplace with your admin account
Go to the "Payment system" then "Stripe" or "PayPal" pages in your Admin panel
Click Disable Stripe or Disable PayPal
Read and accept the warning message if you want to move forward
That's it! You should now contact your providers to let them know.
Note that if no payment system has been connected then this will not be an option and if only one payment gateway has been connected in your marketplace so far, the best way to stop using payments is to entirely disable the online payment system.
What happens when a gateway has been disabled?
Immediately after you've disabled Stripe or PayPal:
providers can no longer edit or add their payment details in their user settings
providers payment details are not deleted so they can be restored if you want to enable the payment provider again later
buyer can no longer pay via the gateway you've disabled
ongoing transactions will continue as expected and won't be stopped or closed
if providers had enabled only the payment gateway you've disabled, buyers can't pay for their listing, and they should connect their payment details for the other enabled payment provider from their user settings
providers are not notified automatically of your choice to disable a payment gateway
How to enable again a payment gateway that has been disabled
From the same Admin panel pages, you can click the Enable Stripe or Enable PayPal button. It will be enabled immediately.