@Trixster
Some colleges have extra curricular research programs for high schoolers, like Vanderbilt.
Perhaps there is something near you, or even online.
There are some for profit programs that come up, too, surely fee based.
Some federal or state agencies may have unpaid research internships.
For example, NASA, NIH.
See NASA’s Datanauts program for example
See STEM engagement for high schoolers, set search filters. Datanauts
Also, the Army has programs. Students | AEOP