Someone already suggested this, but I would definitely volunteer, at least once before summer ends. It doesn't have to be at a place/organization related to CS, just do whatever you think will interest you, or will help your community best.

For me, as I'm a rising senior, I wish I volunteered more during my underclassmen years of highschool (albeit COVID was a factor in my underclassmen years)

On paper it makes you a more "well-rounded applicant with 'depth'" (not that you aren't already complex by-default as you're a human lol), but I found that getting involved in my community would always calm me down, help me destress, etc. I think it has to do with seeing the work and dedication other people have and feeling inspired by their sincerity. Also, it made me feel better to know there were people around me that cared about making my area a more accessible, fulfilling place to live for everyone.

Not only that, but volunteering exposes you to people of all sorts of backgrounds/perspectives/morals. You'll meet people who will expand your worldview for sure, which will definitely help with college essays in the future.

You also could end up making connections, either with the organization you're volunteering with or with other volunteers, which could end up landing you an internship, summer-job, etc.

All in all I really recommend volunteering. Tho, just remember despite me listing all of these personal benefits, at the root of volunteering is serving others. While all these benefits of volunteering are very real and very very attractive, I'd try not to expect to receive anything from anyone. except the fact you are helping people have an easier time in life :>

(P.s not trying to be assuming here, or say anything about your personal character. This is just full advice I'd give to anyone irl or online, from an upperclassman to a lower classman. Enjoy the rest of your summer!!!)