Different maxlengths in different paragraph contexts

We have a paragraph type that mimics a field group; it's re-used inside other paragraph types.

If we apply a maxlength to a field in that sub-paragraph type, it's used for all of the containing paragraph types. But we want it set differently inside different paragraph types.

What's the best way to modify the length per containing paragraph? Can it be done in a widget form alter?

Thanks in advance!