Okay, I believe I now get what your problem is. Sorry, the question was not clear at first.
So you initially created a Blueprint exposable variable and then changed its value in the editor, later you decided to make it a UPROPERTY(Config) instead and now the Editor doesn’t update to the new value which is set in the .ini file? is that correct? Well, I’ve personally never faced such problem before but maybe the following approach can help you fix this issue:
Change it back to EditDefaultsOnly and make it blueprint exposable. Compile and go to your file, find the variable in the details panel, click that yellow arrow in front of it to reset to its original value. Compile and go back to your C++, make it Config and try again and see if it now reads the Config value from .ini file.
I understand that in your case you’re changing the UPROPERTY and do not expose it to blueprints only. Maybe it’s a bug that UE keeps that variable in its memory and persists on using the Blueprint value. Anyways, as I’ve also noticed, in Unreal once you create a blueprint based on your C++ class, and change the exposable variables inside that blueprint, Unreal will persist on using that changed value and will not read the C++ value anymore even if you go back to your code and change its default value in C++. For each of these variables that you changed their value in BP, you would have to manually reset them by clicking on that yellow arrow.
Hope this can help you resolve your issue.