Extremely long time lurker here. For once I might have something to contribute rather than leeching off everyone's knowledge.
I got Techstream to work on my M1 Mac with the downloads linked in the OP and
this cable off Amazon.
Like others, I got stuck with getting Techstream to open and recognize the connection. In the end, I found a second image of the Techstream program in the start menu. Using that second launch button, I was able to get into Techstream (ignore any prompt to add a product key) and switch over the USB preference to MVCI, which then allowed me to connect my cruiser to the Techstream app via the launch button on the virtual machine home page.