I think you make a great point in highlighting the value of Regex. I don't want to undermine it at all, although some use-cases are just not a good fit for it (even if you can horseshoe things). I think a higher-level abstraction for regex is super welcome, and I quite admire what you are doing there, thanks a lot for sharing. I do think regex's indeed quite a lot more difficult to grasp when complexity rises compared to grammars or other approaches.

Worth looking into nested words aka visibly pushdown languages.

They're a proper superset of regular languages and a proper subset of deterministic context-free languages, but they retain many of the nice properties of regular languages that DCFLs don't - they're closed under intersection, union, concatenation, Kleene Star and reversal.

They can parse more languages that Regular Expressions (non PCRE), but fewer than deterministic CFG subsets like LL/LR. They're expressive enough to parse languages which have a regular tree structure like S-expressions, JSON, XHTML.