The whole context of "quishing" seems pretty stupid to me. Any link on the internet can lead to a phishing page. Ads lead to phishing page. Search results lead to phishing pages. URL shorteners lead to phishing page. There is nothing special about QR codes.

If you want to be safe from phishing, there is only one advice which is always good: don't enter confidential info if you did not initiate contact. Don't tell your credit card numbers to people who called you, find their phone number somewhere and call back. Don't enter your bank credentials after clicking the ad (or scanning QR code) - open a new tab and enter bank's URL (or use bookmarks).