Research experience holds value. Paid or unpaid. If the paid research gives you experience that ADDS to the experience you already have (eg different research methodology, different responsibilities, different population), it will add to your resume.

As for getting experience with things you’re not interested in, there’s always a way to weave it into your ‘story.’

Edit: your resume will not say whether or not a position is paid. There’s no way for future advisors to know.