Hello jmocampo,
We understand your iPad was displaying as charged and not charged after connecting it to your MacBook Air to use Sidecar. We also understand you used Terminal, and after doing so, your iPad says it isn't charging.
To start, we'd recommend completing the steps on what to do If your iPad won't charge.
If you're able to charge your iPad using a power outlet, we'd recommend letting your iPad charge for at least an hour before trying to connect it to your Mac.
If you're unable to charge your iPad using a power outlet, your Mac, or a compatible Apple-certified accessory, please check your charging cable and USB adapter for signs of damage, like breakage or bent prongs. We'd also recommend trying different cables and adapters to see if you can isolate the cause of this behavior.
If needed, please see How to clean your Apple products for steps on how to remove any debris from the charging port on the bottom of your iPad.
If you're still unable to charge your iPad, it may require service. This link can help with reviewing service options: iPad Services and Repair
If you're able to charge your iPad using a power outlet, or a different cable or adapter, please try to Use your iPad as a second display for your Mac with Sidecar again.
Cheers!