Hi,
Please find below the access to the demo page. With the old payment plugin (which is outdated) it works. With the new paypal-payment plugin from WooCommerce it doesn’t work with the woodmart theme. With other themes it works without any issues.

Maybe this information will help – however, it did not work on our end:
https://wordpress.org/support/topic/paypal-button-single-product-page-incorrect-position/