I am a bit worried about people losing money and trying to blame me. I will think about keeping this tool online or not. I would like to listen to your feedback NotATether, as you requested it.
I knew that one day you would start doing more serious things
You can do your best in mistake prevention, for example
You need to add a "paste" button where the address is entered. There are many cases where this is useful.
Also, the "copy" button to memorize the payment link.
I'm not sure what type of field you used to enter the Bitcoin address, but when I clicked, I was offered a street address from the browser cache from who knows when. You should probably turn this off because it can also bring unnecessary complications.
As an additional security layer, you can make a small tool to verify what the user has copied. So, immediately on the same side, the field for input and check. The user enters the link he copied, and your script checks if it matches the string from the "share" field