Removing part of uri using htaccess and then using it as query parameter

How do i remove just part of uri and substitute it with a query param?

I want to change:

https://example.com/guest/s/myvalue/?id=something&name=somethingelse

To this:

https://example.com/?id=something&name=somethingelse&myvalue=myvaue

Ive tried every possible combination of regex and rewrite methods but doesnt do what i need.

Thank you in advance