There is possibly some corruption within the back files (the files that support the .aia). It is very difficult to ensure that a corrupted file is 100% clean. In the time already taken up trying to fix your files, a new one started from scratch could be well on it's way.
There is a common saying from many years ago. It is not meant to be rude or insult, but to get an important message across.
I agree with your KISS but, I am wondering for any solution, if I don't get fix them I want solution for transfer blocks and designs to another project easily, if that also won't work then I will think about recreations.
If you try to use anything from your other files, behind the scenes you could be carrying across the corruption. That is why you should start again, from scratch, brand new file.
Define your App on paper first - what is the minimum functionality required?
Define snippets in App Inventor and test them. When satisfied that they work as required in all circumstances, bring them together as one file. For example, that Scan feature you added to your Project. Make a test App just for that feature to ensure you have everything just right.
"More haste, less speed." When one is in a hurry, one often ends up having less success and completing a task more slowly.
Ripping out extensions, procedures, and variables can be tricky in AI2.
Unlike a movie where the bad guy gets to plunge his hand into his opponent's chest and grab his heart, surgeons need to use clamps to localize their work.
(I recently had to have a shower valve replaced, and had to turn off water to the whole house because I could not locate any cut off valves for the bathroom.)
Similarly, to code for risk reduction, you would need the equivalent of those submarine doors with the big wheel, to compartmentalize your app in the case of a breach.
In the case of extensions, I would hide their use behind procedures that call them, and just call the wrapper procedures. That way, only the wrapper procedures suffer when the extension is removed.
It's better to follow the other Power Users' advice, and start fresh, only adding items that have been unit tested in various environments before a system test.
you updated silver extension or similar but somehow you installed project instead of a aix extension, it can be seen in this aia
This error is due to outdated extension somehow you reverted back to an old version in the above aia
This KinnkoMultiFun1.aia (453.5 KB) works in companion on android 9 but NOT on Android 14 and that because of AlphaDialog extension, there seems to be a issue using it with Android 14, same with this extension DaffyDialog