Emailing professors for a summer internship?

I’m a HS junior who basically got rejected from every single summer activity I applied to so now I’m at a loss for what to do.

I guess my last resort is emailing professors for a summer internship. I’m primarily interested in statistics, business, and finance. Does anyone have any links to other threads or templates for emailing professors? Is it better to target an assistant professor versus an older, full professor for the best shot at obtaining a HS internship? Also, should I tell them that I’d be willing to work unpaid? I honestly just need some kind of work experience this summer, so I don’t care if I’m unpaid.