I had idea of making adapters that have barrel jack on one side and USB-C port on the other. The 5V ones would be easier but would need ones for different volta

I had idea of making adapters that have barrel jack on one side and USB-C port on the other. The 5V ones would be easier but would need ones for different voltages, which would either need USB-PD PPS or transformer in the adapter. They would currently be expensive and only for people who really hate wall warts. The other problem is that multi-port USB-C chargers are rare and expensive. My impression is that most devices with barrel ports don't use that much power and would be fine without USB-PD. They use barrel ports because they were designed before USB-C or because USB-C port is too expensive. I supsect many would be fine with USB-C to USB-A cable and charger.