Starting November 2023, all new installs of WooCommerce will default to a new block-based Checkout page.
For payment methods to show here, they need to have additional compatibility for this page. Currently, most payment plugins, including PeachPay, do not fully support this new checkout page.
As a result, you might see a message "There are no payment methods available. This may be an error on our side. Please contact us if you need any help placing your order."
Or, you might see some payment methods, but others are missing. If you click on the payment options block, you'll see in the sidebar which payment methods are incompatible.
You can go back to the old checkout page by clicking Switch to classic checkout. After switching, click Update to save the changes.