I got it to work with ChatGPT, took around 5 attempts, but that was mainly me not understanding all the edge cases. Once I came up with a strategy that would work, ChatGPT gave me working code.

My strategy was not efficient, but did work.

I walked the string twice, first LTR and replaced all found strings with numbers, then walked right to left, and replaced all backwards strings to numbers.

Then took the first digit from the left walked string, and the last from the right walked string.