So I attempted to review this but I think you have a massive number of thread safety issues. I got thousands of exceptions - some concurrent modification, some sequence contained no matching element, and various others - while analyzing, and then when it finished and tried to write the assemblies, I got an AggregateException with 2588 inner exceptions, most of which were either MemberNotImportedException, or IL_[offset] references an offset that is not present in the method body.

From a quick look, you're using one _ilGenerator in AsmResolverDllOutputFormatIlRecovery.FillMethodBody, but that method is called in parallel so you've got multiple calls to it at once, which it can't handle - e.g. it maintains an _importer field which is being overwritten constantly, so methods are being imported into the wrong modules. Seems you'll have to pass that through.

The control flow graphs I did get (I uncommented the line which wrote them, so that I could evaluate the decompilation in at least some way) looked promising, though they were much more complex and I didn't have much time to familiarise myself with the string representations you were using.

For reference, I was attempting to decompile AUDICA.