However, barring $eval and with JSONata's design choice that a regex/pattern is a function, it seems there is no way to convert an inert JSON string such as "^s3://my-bucket/" to a regular expression ...

Not surprisingly, Javascript, with its origins in web programming, has one of the most robust regular expression (or, more colloquially, regex) libraries in use today, and recent developments in ...

It's been a while since I worked on regexs in JavaScript, but generally the way you do this in most programming languages is to build the regex as a string and then pass it into the regex engine.