Does Excel VBA Application.ScreenUpdating affect applications?

Question

Visual Basic

Good afternoon!
Excel runs a large macro of a dozen modules and functions, many of which use Application.ScreenUpdating=True/False to speed things up.
There is also another macro that calls the first one in the loop (for testing purposes).
Problem: while the second macro is running, some applications (Word, Outlook were noticed) are "not active", but there is no "not responding" status or the like, while the Word file can be selected from Explorer (there are no problems with it), but further in this file, nothing is pressed, without any reaction.
Question: can this behavior be related to the Application.ScreenUpdating option.
Also an additional question: can the speed of macro execution depend on the fact that other files with large macros are open? (Example: 3 files are open, the macro speed in one of them is 5 seconds. If you close unnecessary files, the speed will be 1 second).
There is no way to post macros for various reasons.