Hacker News Reader

they sell modules on AliExpress that claim to do that

https://a.aliexpress.com/_Ez4GjPQ

and some powerbanks advertise passthrough charging eg. https://amzn.eu/d/hApICf9

That one, sadly, does not have USB-C output, so it's fine for something you're wiring up custom but isn't a generic solution (which, to be fair, is the quite niche overlap of wanting to power something with USB-C without a battery and wanting battery backup).

Reply on news.ycombinator.com