View the web.config used in the farm

I recently faced an issue with the workflows of SharePoint 2013 on premises(2 WFE and 1 App Server). They have stopped working and the problem is a .NET security update. Microsoft has a script for this but I want to manually update all the web.config files as I cannot keep a backup before running the script. Please, could you assist me in the following questions:

  1. How to find all the web.config files that are used by the farm?

  2. Besides the WFE servers, should I also update the web.config in the App Server

  3. After the operation, is an iisreset necessary?

  4. Do you recommend running the script instead of updating manually?

This is the link to the issue and the script:

https://support.microsoft.com/en-us/help/4465015/sharepoint-workflows-stop-after-cve-2018-8421-security-update