I had the project imported, but the first thing I wanted to do was to rename it.  I have the habit of looking at library code as if it were a real library book:  I hate to mark it up!  I have to rename it and file the serial numbers off of it before I'm comfortable working on it.  The only problem.  You can't do it.

If you highlight your project and right click, there is a rename option.  It fails.

A kind fellow user on the STM32 community forums gave me this workaround, which I'll describe as follows.

In your system's file explorer, find your workspace and open your project folder.  Find the folder named "STM32CubeIDE" and open that.  There should be a file named ".project".  With a separate text editor, open that file.

In this XML file, find the <name> tag. It's right at the head of the file, line number 3.  Inside the tag is the original project's name.  Change it to the new name as needed.  This is the only change you need to make.  Save the file and close the editor.

Now, while you still have your file explorer open, click on the .project file you just edited. CubeIDE will create a new project and copy all the files over from the original project.

(You might want to have a separate text editor besides CubeIDE, if you aren't already using one.  I use Visual Studio Code.)

This tip might be applicable to other Eclipse derivatives.  If your toolchain uses Eclipse (it's usually not a secret if it does), you might want to try it.  (This could have come from an Eclipse user group for all I know.)

I just remembered that I haven't really described the hardware, specifically the STM32H735G Discovery Kit.  When I bought the board, I searched for projects using the board, and I only came up with projects from ST Micro themselves.  The board doesn't seem to have many users out in the field--or rather, not many users in the hobby electronics or hacking communities.  I'll fix this and describe the board next time.