Hey - Is this still an issue? We use both Shopify Online & POS and use gift cards (both physical and digital) which are useable online and in-store so I’m sure I could answer this but I’m not 100% sure exactly what you’re asking / trying to achieve.
For our physical gift cards, we have created a design our selves and have a printer that produces them with a QR code / serial number. When they’re sold, the QR code is scanned at the POS to ‘sell’ the gift card and then it can be redeemed in-store using the QR code at the POS or the customer can use the serial number online.