508 remediation of Storyline course

Hello ContractsManage​ . Your post deserves to stay at the top of the list for as long as possible to get answers and gather useful tips.
We all struggle with these kinds of problems.
I don't have a magic formula. 
Regarding your X icon that needs to be enlarged: if it needed to be shrunk, there would be a trick. But I don't know of a way to change the size of 508 elements on 508 different slides, even if they are all identical and only appear once in the Media Library. I don't think it's possible... (see below).

However, using the Media Library, you can find your X icon element in the list, write alternative text, AND CLICK on “Apply to All” (apply the text to all occurrences of this media). This way, with a single click, all your X icons will share the same alt text. BUT not all icons will become accessible if they are not already. You have to do it slide by slide...

Now, for resizing, I thought that an alternative solution might work with JScode. I'll look into it. Since all X icons (now) share the same alt text, they can all be targeted by code that would resize them (height and width) and reposition them on the slide (roughly at the top right, adjustable in the code) at the beginning of the slide. These are simple things that code can easily do, in theory. I'll get back to you when (if) I get a result.

This morning, ChatGPT failed miserably at writing this simple code. If anyone feels up to the task, please give it a try. For my part, I'm going to find a small piece of code that does the job (moving an element, for example) and continue discussing it with ChatGPT.