I think it may be too early to start thinking about internships that far ahead for a number for reasons. One reason is that lot of such internships don't become available till close to date of their need as providers of these internships need to budget for it, if they are paying or approve unpaid ones for departments when they need them. So it's like shooting in the dark when some of the internships don't even exist right now but like flowers in spring will bloom when it's close that time (summer 2023). Which means you may be able to find internships for summer 22 because that is what will be in currently in need. The other reason is that there are many college level students gunning for those internships and may have a better chance given that they would have more relevant knowledge having taken those college classes.
With that said, there are still lot of internships out there specific to high school students that you can get start on right now. And come end of summer 2022, you can start your hunt for summer 2023 opportunities. For now check these out:
24 Awesome Internships for High School Students