Really? That's the only way to get back functionality that worked perfectly before the update? As I mentioned before, it worked with Joomshaper 3.x well, so it seems to be a problem of the new version...
The slideshow looks fine in the backend but saving the changes doesn't end up in correct code.
As you can see in the next screenshot
https://prnt.sc/cTw9V5alJ-hm
in the marked line, the color code for the background is "ffffffpx", where it shoud be "'ffffff" - why the software is adding that "px", I don't know, but that might be the problem, for that is an incorrect (and therefore ignored) value. Perhaps you could have a look at that. Thank you.