Yeah, that would be it for sure! Not only is the USB (most likely A, not C) port not Power Delivery protocol, it's very likely limited to 2.5W of power. Computers are not USB power banks. 😁
You need a good PD charger, I'd recommend getting...
The linked article is about US Dept of Commerce which had a proposal to ban the import of Chinese made drones but they just withdrew that proposal. This is completely independent of the FCC covered list which is still intact.
And the plot thickens. Don’t get too excited because this doesn’t help DJI customers but it does show things continue to be dynamic.
FCC Exempts Some Foreign Made Drones