I did go down the Git local repository path but abandoned it for couple of reasons. I did not share the entire background of what caused the crashes. We had implemented magento as subfolder under the root. I wanted to remove magento from our URL path. Reading through different forums, it seemed pretty common request, and how to resolve it seemed pretty straight forward. I changed the Web URL configuration in Magento 2. Since then the Admin Panel had been crashing, and I had been restoring it as described here. I knew there was correlation between what we changed in the URL and Admin Panel crashes, but could not pin point. Yesterday, I did regression tweaking and back tracking everything that we changed in Web URL. The key was that I had changed not just the Web Base URL (secure/unsecure) but also Web Base Link URL (secure/unsecure), and had unchecked 'Use system Value'.
Also the core_config_data table entries reflected the URLs without the word magento, but the Admin Panel always had the word magento in its URL path, with the settings as stated above.
I checked the 'Use System Value', and saved the configuration. The Admin Panel came up like it used to. The system automatically deleted the entries for Web Base Link URL (secure/unsecure) in core_config_data table. Since then both the application and Admin Panel are stable. It resolved this issue, although the other posted issue remains: Redirect Magento2 from subfolder to root folder.
I belive that I can resolve it by simply editing the Web Base URL (secure/unsecure), and not touch the Base Link URL (secure/unsecure), or the 'use system value' checkbox.
What I am not clear is the significance of these fields Base Link URL and Use System Value .