The best cleaner for cleaning grimy dirt like that is K&N air filter cleaner. There is no such thing as ocd when it comes to cleanliness just different standards of cleanliness. Its only a few 1' by 1' areas in the pictures. After I clean my engine bay areas I polish them a bit with cleaner wax so they repel dirt so you don't have to clean as often. But you can put that K&N air filter on oily greasy dirt & it will dissolve & wash away the worst gunk & make it look clean. That's my secret cleaner.