RegEx in Javascript, Match multiline text between Tokens

With ((.|\n|\r)*?) you’re saying to take only the first character – a space, in the example.

On the other hand, ((.|\n|\r)*) you take any amount of characters (wich includes 2025-11-13too).

So you need a condition to stop:

.(?!^\d{4}-\d{2}-\d{2})

…tells to match any amount of characters if the current position is not of kind ^\d{4}-\d{2}-\d{2}.

Like said by @Barmar, you can simple use . with the s flag in replace to (.|\n|\r).
You’r code:

/^\d{4}-\d{2}-\d{2} ([a-z,]*)(.(?!^\d{4}-\d{2}-\d{2}))*/smig