You're describing the exact use case for a dedicated crypto payment processor. The good ones work just like Stripe for crypto: you (or your dev) integrate their API or plugins. A customer pays with crypto, the processor instantly converts it at the current rate (so you avoid volatility risk), and deposits the fiat to your bank. They handle all the blockchain complexity. For a business-focused solution that's built for this kind of integration, you should check out https://paybis.com/business/payment-processing/. It's designed to automate the entire flow from crypto payment to your local currency settlement, which is what you need.