Backtracking regular expressions as an intentional or accidental DOS vector are a moderately well-known issue, and while I prefer that a standard library implementation be robust against them, I can see the POV that it's buyer beware.
Converting a string to an integer is somewhat less well known as a DOS vector, more painful to avoid as an application creator, and easier to fix in code.
So there's a cost-benefit argument that you should just do this before you rewrite your regex engine.
On the other hands, lots of buyers are not aware that it's an issue, and more frustratingly there are regex engines which are very resilient to it... but are not widely used.
Python's stdlib will fall over on any exponential backtracking pattern, but last time I tried to make postgres fall over I didn't succeed. Even though it does have lookahead, lookbehind, and backrefs, so should be sensible to the issue (aka it's not a pure DFA).
Converting a string to an integer is somewhat less well known as a DOS vector, more painful to avoid as an application creator, and easier to fix in code.
So there's a cost-benefit argument that you should just do this before you rewrite your regex engine.