Gentlemen,
Thank you so much for your guidance. I did as indicated, but, I was reusing my backup to keep trying new solutions, which has not worked so far, 7 hours after the crash. If I removed the whole Tax plug-in, then another plugin started yelling for attention, and so on...
After nine hours of futile troubleshooting, I tried one more time with a new database restore from the day before and a fresh GIT clone of the previous save and decided to simply ran it in Debug Mode. Low-and-behold, as they say, the code kept turning and the debug supporting files were recreated and restored and pow, the landing page sowed-up. OMGosh, that was like having a bright light ignited over the whole room.
After that initial successful launch, I retired two more times in Debug, and finally ran a launch without debug and that worked too.
Publishing it to the IIS Server also finally worked. WOW! That was quite a scare.
Now that it is back-up and working on IIS, I was wondering if I should upgrade to version 4.5. Right now, I am on here:
<TargetFramework>netcoreapp2.2</TargetFramework>
<Copyright>Copyright © Nop Solutions, Ltd</Copyright>
<Company>Nop Solutions, Ltd</Company>
<Authors>Nop Solutions, Ltd</Authors>
<Version>4.2.0.0</Version>
Any Ideas on how I could go forward to successfully upgrade without breaking everything?