You can get a very nice XLR to USB “adapter” (actually a whole mic preamp, phantom power circuit, plus external “sound card”) all in one small piece).
https://www.markertek.com/Cables/Computer-Data-Cables/USB-Cables/US-Music-Corp/STUSBXLR10.xhtml (but I don’t think this one does phantom power)
https://www.markertek.com/Audio-Equipment/Audio-Interface/Computer-Audio-Interface/MXL-Microphones/DYNAMIC-MICMATE.xhtml (it looks like this one doesn’t do phantom power, either)
https://www.markertek.com/Audio-Equipment/Microphones/USB-Microphones/Blue-Microphones/ICICLE.xhtml
https://www.markertek.com/Connectors-Adapters/Data-Connectors-Adapters/USB-Adapters/Shure-Inc/X2U.xhtml
There are probably more brands and models like this available, and from several other vendors besides Markertek.
You will easily spend more on just a phantom power “injector”. I have no clue how they can get so much $$$ for such simple things.
There is a VAST difference between an external USB-based audio interface and the one built into your computer. Night and day. The mic preamp built into your computer is good enough for communications (like Skype, voice-mail, etc.) but by no means suitable for serious recording of ANYTHING.
There is also a USB version of the AT2020. The AT2020USB. It has that mic preamp, phantom power circuit, and audio interface all built right into the mic.