MacBook Pro 2018 13" - Connect to three monitors?

No. You can support the internal and two simultaneous external displays at up to 4K. At best, you could find a splitter to mirror one, but you cannot run three separate displays. Well, not well – there are USB-driven display options but they work only with low resolutions, slow refresh and are very laggy.

if you require three external displays, you need a recent model 15”/16” MacBook Pro. For example, my mid-2017 15” and my new 16” both support up to four external displays.

When Apple says it supports a display, they are providing an accelerated Hardware interface to re-draw that screen 60 times a second. It will not be ANY of those pejorative words. The mouse will track perfectly. It will be visually excellent.

Unless you load up your computer with Junk.

Grant Bennet-Alder wrote:

When Apple says it supports a display, they are providing an accelerated Hardware interface to re-draw that screen 60 times a second. It will not be ANY of those pejorative words. The mouse will track perfectly. It will be visually excellent.

OP is asking about adding third display, to a Mac that only supports two. From my experience, adding an extra unsupported display through a USB ‘external graphics’ solution deserves lots of pejorative words.

sorry, I missed that the question was for a 'faked' (all in software) USB display.

Some users find that the mouse-tracking on 'faked' USB displays make them "seasick"**

You could put static stock quotes on it, or a program listing you are NOT editing, but moving pictures might be a mistake.

**laundered for the swears filter.

I think it will only work with two displays because your video card may only be able to handle the output of two displays.

Depends on the adapter. Looking at ones I’m familiar with (StarTech, Pluggable), it’s not even clear they work with Catalina.

Have you considered an iPad and Sidecar?

Gjc