Have you tried Work at a Startup?

https://www.ycombinator.com/jobs

You can apply for internship roles there (by configuring it in your profile).

cold dms and emails are what landed me (senior in hs) YC internship, and honestly just being within the community and showing passion about the product helps drastically

>Any advice?

Yeah, don't put YC on a pedestal. Whatever ship the supposed prestige was on sailed a long time ago, then sank.

One would hope that would create a habitable reef, but in practice it's probably closer to an underwater super fund site.

>...and I've also built and scaled consumer mobile apps solo to 20k+ downloads

I highly recommend watching HBO's Silicon Valley.

good luck