Opinion:

BitPay was a horrible choice. BitPay has a history of being a bad actor in the space (e.g., opposed SegWit) and are a purveyor of shitcoins (and therefore will never add Lightning network support). OpenNode, or another from the handful of other merchant payment processors out there, would have been a much better choice.

Sling is also a horrible choice. So they accept bitcoin and cryptocurrencies only for prepaid subscription plans (with a one-time on-demand payment so that the current month's post-pay bill can be paid off, and then prepayment for subsequent months can be performed).