[brendanmc6]

Paying with ETH is the easy part— few lines of javascript using Ethers.js

The hard part is managing wallet connections, and then automating what happens after payment is complete.

For wallet connections I use web3modal.

For reconciling the purchase after payment, no clue. I use coingate for crypto checkouts for this reason. There are probably backend libraries out there to help you track and respond to transaction events on a given address. Let me know what you find!