Anyone experiencing denied purchases when using PayPal as the payment option?

I tried splitting the payment between two Platinum cards and even using finance into four payments, but the Oura checkout would display a generic error banner saying it was unable to complete checkout and to contact support. I first chalked it up to a late‑night checkout/website issue, but it has been persistent over the course of the week. I’m suspecting Oura is not keen on PayPal as a checkout option.

Any suggestions on how to use the Amex credit?