remain order as on-hold

Hello,

WooCommerce core by default will change an order from on hold to completed once the payment is clear and order is fulfilled, an order that is on hold means, awaiting payment – stock is reduced, but you need to confirm payment.

Source: https://woocommerce.com/document/managing-orders/#order-statuses

There is a premium extension that will help you to manage custom order statuses, called WooCommerce Order Status Manager, https://woocommerce.com/products/woocommerce-order-status-manager/

I understand this is not exactly what you are looking for, but that could be a work-around.

Let us know if there are any questions.