DC voted 93% for Harris. It will get more conservative only because it could not get more Democratic.
With a Republican administration, DC will be a less attractive place for the young and ideological post-college grad progressives to come for work. The real impact won’t be felt until 2028 though. Because back to back Republican administrations will have a big effect on the balance of power and money in the city that will influence jobs, policy, politics and career choices in a more fundamental way.
This is where the pipeline of new grads dries up and existing residents who work in politics related areas start to move away.