Optional chaining was only introduced to javascript in April 2020, 18 months ago. That's a pretty gnarly upgrade cycle to demand all your general-public users maintain.

Alright, I agree, that is probably too recent to be breaking stuff. But I maintain that no one should be running an out of date browser in the first place.

In fact, browsers that are more than X months old should automatically pop up a warning telling the user that it hasn't been updated recently and they're running a security risk by continuing to use it, including/especially on these old EOL devices. Browsers that have reached this point shouldn't be expected to be supported by websites.