Since 202 covers all of DC since 1947, why do lookup tools show nearby MD cities like Germantown or even Seattle for these numbers? Is it VoIP spoofing or did they change the physical borders?

The Seattle thing is just a lazy glitch where databases mix up Washington DC and WA state. But showing Maryland cities like Germantown is totally normal now! Over the years, cell routing and number porting mean people living in the MD suburbs (originally 301/240/227) can easily keep or get a DC 202 number, especially with VoIP. To see the actual carrier and exact current location behind a specific number, try this link.