Maybe you can reinstall the server and run a /Mode:RecoverServer switch, after the installation you can try to uninstall it the correct way.
This is for 2019, but steps on that should still be same:
https://docs.microsoft.com/en-us/exchange/high-availability/disaster-recovery/recover-exchange-servers?view=exchserver-2019
If that fails, try these steps:
https://messageflip.wordpress.com/2010/07/30/exchange-2007-cant-uninstall-cant-reinstall/
If its an old dead server then remove it from AD using ADSIEdit and perform the uninstall again :)
I only have one - if you have a second entry for this server delete it from here;
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