I'm sorry to hear you're still having problems with Juicebox-Pro under macOS Sonoma 14.6.
Unfortunately, I do not have access to a Mac running macOS Sonoma 14.6 so I'm running blind here but I'll do what I can.
If my suggestion from your other thread did not help (to manually remove the ELS folder with JuiceboxBuilder-Pro closed), then I think it's unlikely that I'm going to be able to resolve your problems quickly but a little more information should help me construct a detailed bug report for the developers.
When I adjust parameters like nav icon color and position, nothing is visible in the Juicebox window.
When you say "nothing is visible", do you mean absolutely nothing is visible (a sign that AIR v51 is being used instead of AIR v33) or that the changes are not reflected in the live preview? Do all parameters fail to update in the live preview (even non-color and non-positional ones like the Gallery Title) or do some work? (The live preview should be updated when a parameter's input loses focus and this should be the same for all parameters.)
The Back button is invisible no matter what I do. Both in WSYWYG and in the actual galleries.
Is the Back Button simply not displayed at all or is the background visible with no icon (or is the icon visible with no background)? The Back Button is a character in a custom font, just like the icons on the Button Bar. If the Button Bar displays OK, then the Back Button should, too (in theory). Could you please check to see if the Back Button icon's color matches that of the background (which would render it invisible)?
When you say the Back Button is invisible in "actual galleries", have you checked in browsers other than Safari? If it is invisible in all browsers, then it sounds like it might me a gallery configuration problem of some kind. If this is the case, then please post a link to your gallery so that I can investigate further and hopefully propose a solution (at least to this problem).
The save and load preset dialogs are broken.
I thought that deleting the ELS folder (with JuiceboxBuilder-Pro closed) might help with this but I guess not. Sorry.
If you save over a preset, there is no standard overwrite warning.
I would have thought that JuiceboxBuilder-Pro uses a native Mac file chooser dialog to handle the loading and saving of presets (as it does on Windows). If this dialog does not warn of a possible overwrite, then this sounds like it might be a Mac bug out of our control.
What is the point of this AIR rigamarole?
As I'm sure you're aware, JuiceboxBuilder-Pro was written as an AIR app and needs AIR to work.
Any alternative would require a completely new program to be written from the ground up.
Sorry for so many questions when I know you want (and need) answers but with more information, I can at least contact the developers with a detailed bug report.
In the meantime, please post a link to a gallery with an invisible Back Button and I'll report back with what I see on my Windows PC (in all the different browsers I have installed). I might be able to resolve this problem at least. (It sounds too specific to be a macOS Sonoma 14.6 problem when everything else seems to work fine in the actual galleries.) Thanks.