The sudoku example has something massively wrong with it's performance. Latency is over a second per click and it halts after a few clicks.

The QR example works fine though

Do you really think this "works great"?

I'm using a brand-new MacBook Pro with a high-end M5 processor, and this site is extremely unresponsive for me. Huge latency between clicking and getting feedback.

It also breaks accessibility.

The QR code use case seems far more reasonable to me, you're generating a static image.