The scan result is copy-only
A text QR has no destination. All it carries is characters, so scanning displays them on screen for the user to copy and use. It's a different thing from a link that opens a web page.
This site's scanner works exactly that way. It offers an "open" button only when the scanned value is an address starting with http or https; every other value is treated as text you can copy but not launch.
Why only links can be opened
It's a deliberate safety gate. You can't read a QR code with your eyes, so if a scanner would act on any value it found, people would be tapping without knowing what they're about to open. Values like javascript: or data:, which can run code in a browser, are the obvious hazard.
That's why this site attaches an open button only to values verified as http or https web addresses. Everything else is simply shown as-is, letting you read it, judge it, and decide what to do yourself. Text QR codes being copy-only isn't a missing feature — it's the result of that design.
Keep it short so it scans well
More characters mean more modules in the same area, and smaller modules are harder for a camera to read. Text QR codes place no limit on what you type, which makes them the type most likely to run into this ceiling. Non-English characters take up more space per character, so they get dense faster.
Short, fixed values fit best: product serial numbers, asset tags, seat or equipment identifiers. If your notice starts running long, put the full text on a web page and link to it with a URL QR — that's how you get a code that still reads at small print sizes.