<blink>Blink</blink> -- It's a deprecated tag now, and most browsers don't support it, but I would have loved to have seen that as a company... <marquee> is still supported though....
FWIW for most of these sorts of things you can scrub it via passing the text through an NFKC or NFKD transform. I'd hope that a screen reader can be updated to handle this case.
These are Unicode characters intended for use in mathematical formulas, not text, so they break all sorts of things. It might make some sense to use them in mathematical Python code (where they do seem to work), but they're hard to type.