Thanks for asking!
As a general statement, no - here’s why: USB graphics adapters like the UGA-2K-A are separate graphics devices from a hardware perspective. But from a driver perspective, they make use of the CPU and main GPU on your system to do all the graphics rendering, before sending the final changes to the image out over USB.
So displays attached over USB will not have better rendering speed than your main GPU.
What they can do better, though, is screen resolution. Because USB displays are independent graphics outputs, they actually aren’t limited by the maximum modes of your main GPU. So it’s completely possible to have a laptop (and external connector) limited to something like 1680x1050. But then if you attach a UGA-2K-A, it will still be able to set a full 2048x1152 / 1920x1200 mode on monitors which support that. And it’s lossless compression, so while performance is something to think about, once rendering is done, the pixels will be perfect. So it tends to be great for web and application type uses.
To answer your question more precisely, if you can post make/model of that 28" monitor (or its max mode) and also the laptop (so we know specifically which CPU), we can characterize what the performance is likely to be.
Hope that helps. Thanks again for posting!