My scenario: We've migrated to Exchange 2013 Server, and after migrating, we turned the Exchange 2010 Server off to see whether the 2013 works as hoped for. It did to my relief. Now for my issue. The Exchange 2010 Server won't come online anymore and after a few days of trying to fix the Server/get it online again with a recovery to properly uninstall Exchange 2010 I've come to terms with the fact that I won't get it online again. What happens if I follow the not recommended and unsupported way of manually removing the entires of Exchange 2010? How bad can things go sour? I've spent way too many hours on Exchange, and I'm by far not an expert. At this point, I'm merely a desperate Systemadmin asking for help.
I haven't tried that yet, though my plan now is to recover it the way you suggested and if that doesn't work I'd try the manual removal.
I'm afraid contacting the Support isn't an option, at least that's what I was told, because Microsoft no longer gives support to on premise Exchange Servers. They only way to get support is when you're running a Hybrid/O365 solution.
Thank you for your suggestion and I'll post an answer here once I've gotten around to trying the solution.