SUMMARY
In System Settings → Accessibility → Keyboard Filters → Bounce keys, you can set enable said feature and set a delay that "eats" repeated keys, which is a very useful feature to fight double-click on faulty actual keyboards.

Unfortunately having it enabled messes with other input devices which type in the text, for example barcode scanners (you end up with fake number/text entered, as any repeated characters are eaten, which can catch someone off-guard). Besides barcode scanners, I'm guessing you can imagine other examples of such kind of devices.

The biggest challenge in solving this would be, I'm guessing, trying to properly identify which kinds of devices should be barred from being affected by bouncing keys. Is there some characteristic on USB that can tell it's not actual keyboard? Should certain vendors be blocklisted who make these types of devices but probably not keyboards (such as Zebra, Honeywell, Symbol, Motorola?). I recall libinput has some lists for what kind of mice not to do their debouncing for, but not necessarily for keyboards? Should such a list if so then be maintained solely by KDE?

STEPS TO REPRODUCE
1. Go to System Settings → Accessibility → Keyboard Filters → Bounce keys
2. Enable the feature and set some delay, such as 40 ms, or the default 100 ms even more so
3. Connect a barcode scanner to your machine
4. Try scanning a barcode

OBSERVED RESULT
It's borked! For example (if it's QR code): "htps:/example.com"

EXPECTED RESULT
It shouldn't debounce automated/macroed input devices like barcode scanners, so it should scan properly, despite debouncing real keyboards.

SOFTWARE/OS VERSIONS
Windows: 
macOS: 
(available in the Info Center app, or by running `kinfo` in a terminal window)
Linux/KDE Plasma: Arch Linux
KDE Plasma Version: 6.4.3
KDE Frameworks Version: 6.16.0
Qt Version: 6.9.1

ADDITIONAL INFORMATION
Right now I need to go to settings each time I want to scan a barcode and temporarily disable the bounce keys feature, which is a bit cumbersome, enough to finally report this as a bug. Idk which category it should go into, triagers please help. Can't disable the feature completely, as the double-click on my keyboard would drive me crazy on the other hand.