Well, a little disappointed nobody from Joomshaper suggested a solution to this problem.
So, I was able to determine there is a bug. It appears this is related to licensing. When I open a J4 module and create a SP Pagebuilder page, versus creating the page vis SP Pagebuilder interface, this can cause issues when trying to reopen in the future. My solution, which I tested no less than 12 times, was to open SP Page Builider, then go to modules and open the module. I think the 404 error is that SP Pagebuilder inside the module is looking for the license approval to launch SP Page Builder.
a) would be nice if this gets fixed, its kinda a rudamentary function
b) would be nice if Joomshaper people would respond to critical issues like this. it took me hours to figure out this workaround
M