There's a reason why restaurants quickly returned to physical menus: most of their customers hated QR code menus and the restaurant business is extremely competitive so you have to be responsive to what customers want to stay in business.
It's only in markets that lack competition that a company can do unpopular changes that reduce its costs without losing customers. For example, stadiums all went cashless "for your safety" and then never brought cash back. Which they can do for the same reason they can charge $5 or more for a bottle of water: they're basically a monopoly with a large captive audience.
One issue with QR codes in restaurants is that they force everyone to get on their phones which is sometimes exactly what you are trying to avoid by going out in the first place
I went to a place recently where you ordered on your phone and it kept your tab open until you closed it... I had to race against my phone dying to pay.
It's only in markets that lack competition that a company can do unpopular changes that reduce its costs without losing customers. For example, stadiums all went cashless "for your safety" and then never brought cash back. Which they can do for the same reason they can charge $5 or more for a bottle of water: they're basically a monopoly with a large captive audience.