Zendure calls it "pass-through charging": https://smile.amazon.com/gp/product/B07HB1B4DB https://smile.amazon.com/gp/product/B07HB1B4DB It only has one USB-C

Zendure calls it "pass-through charging": https://smile.amazon.com/gp/product/B07HB1B4DB https://smile.amazon.com/gp/product/B07HB1B4DB It only has one USB-C port, but it can also be charged via a micro-USB port, so you can charge it (if you have a hefty power adapter) and run something from the USB-C port at the same time. I think it will handle up to 18W of power. I use one as a backup power supply for a Raspberry Pi4 and it works quite well. I've never timed how long it lasts but it seems to run for around an hour or two when the power goes out.