Leaving Shopify is the easy half; the payment side is where the work moves. A Lightning checkout settles in seconds and cannot be charged back, which removes the fraud cost that card processing buries inside its percentage. It also hands you the inbound liquidity problem. Channel management becomes the real recurring expense; routing fees are a fraction of a sat by comparison. What I would want to know is whether you keep the sats or convert at checkout. Keeping them makes you a bitcoin business carrying price risk. Converting makes you a fiat shop with a cheaper terminal. Both are defensible positions, but only one of them is a claim about bitcoin.