Hi there @andrewews !
Thank you so much for further clarifying the question here. In short, any customization effort is going to be out of our support scope. Our support staff, myself included, are not developers so it is best that you reach out to professionals who can assist you with this question.
In short, there is a brand guideline for both Apple Pay and Google Pay buttons.
– Apple Pay: https://developer.apple.com/design/human-interface-guidelines/apple-pay/overview/buttons-and-marks/
– Google Pay: https://developers.google.com/pay/api/web/guides/brand-guidelines?hl=en
We have to abide by these guidelines officially. (Stripe plugin still offers customization based on the guideline. Here is our documentation about Apple Pay button as an example: https://woocommerce.com/document/stripe/#express-checkouts-settings)
There isn’t a way for us to consistently say when Apple Pay/Google Pay buttons are not available. It is true Safari and Chrome are the major ones for the Express Pay buttons to show, but there are now Chromium-based browsers out there that behave like Chrome browsers as well.
The main key for Apple Pay/Google Pay buttons to be displayed is that the user has billing information stored on the browser. So even if one has an iPhone, they may not have billing stored to be used on Safari. In such a case, Apple Pay button will not be displayed either. (The same goes to Google Pay)
I hope this clarifies a bit. ??