Howdy Calei,
Great question! Event Tickets Plus actually does not have any settings that impact the payment process for tickets. Instead, it integrates with other e-commerce plugins (like WooCommerce) and relies on those settings for how tickets are processed. In other words, Event Tickets Plus does not touch the purchasing process nor does it have an influence on it — that’s handled entirely by WooCommerce, or whichever e-commerce plugin is being used.
That said, I am not aware of WooCommerce having a setting that allows you to choose the payment method on a product-by-product basis, though I know you can enable multiple payments types and allow the customer to choose which to use.
You may want to dig around to see if there are ways that your e-commerce plugin allows you to enable or disable payment methods on a product-by-product basis. For example, I found this WooCommerce snippet that can disable a payment method by product category, so I imagine there are ways to accomplish this.
Sorry I do not have a solid answer to your question, but does this at least help? Please let me know.
Cheers!
Geoff