For firefox, you can disable IDN in the urlbar with:

    user_pref("network.IDN_show_punycode", true);

in your user.js. Then all URLs will appear in their punycode form, eg apple.com with the cyrillic glyphs will show as:

    https://www.xn--80ak6aa92e.com/

Is this good enough? Probably not in general.

- It relies on you to notice the URL bar after you've clicked a link. Worse, it relies on you to notice the URL bar after you've clicked a link and after the website has begun loading long enough so that firefox changes the URL to the target.

- If you're someone who does actually visit websites with punycoded domains regularly, then this conversely makes it harder for you to know you're on the right domain.

- Even if you notice the URL is wrong, you've already started loading the page. Best case your IP is now known to that server. Worst case it had a malicious payload for your browser / OS / hardware and your content blocker wasn't configured / able to block it.

It's good enough for me, at any rate.