Converting a USB C into a Y-split USB A for chaging
What's the goal here?  If you need to charge a couple USB-A devices then there's far easier ways to do this for not a lot of money.  There's lots of dual port USB-A chargers out there, I found one without much trouble.
https://shop.aukey.com/products/12w-dual-port-usb-wall-charger

If you have to start with USB-C for power there's inexpensive options there too.
https://www.amazon.com/Pengo-Adapter-Transfer-Plug-N-Play-Silver/dp/B07BFQMCVK/

If the power draw from the two ports is less than 5 watts each then it shouldn't be too hard to dig into the USB spec to make each port play like it's an old school (pre-USB-PD) power brick, and have the USB-C side go into a similar "dumb" mode to look like a 10 or 12 watt device to a USB-C power brick.  

With the old USB power bricks they would report their power output capability by having a specified resistance across the data pins, at least as I recall.  USB-C ports on devices support this for backward compatibility.  Depending on how much power this is supposed to handle, and how concerned you are on making this safe from overloading something, this could be trivial to more trouble than it's worth.