You have both so you can stop pacing the floor nights.

The parade represented all of the ten Army Divisions that are combat certified and ready to be deployed. As we saw, marching is not one of their specialties.
Well trained marchers in Washington DC are also well trained Soldiers, Marines -- Sailors and Coast Guard in the Sea Services -- Airmen, Space Force Guardians. They are both rather than one or the other. This is while you presume wrongly it is one dimensional for the Honor Guard units across the services in Washington DC. Your post popping off is wrong because you are uninformed and lazy about researching it.
There is no military specialty of ceremonial guard in the armed forces of the USA. Each guard has a regular Military Occupation Specialty or Rating in the particular service. A number of ceremonial guard members have had combat experience in their particular service.
Ceremonial units in Washington DC march during the summer -- and train to fight and win during the winter when the marching and parade season is slow. Each of the services guards of honor train for and conduct honors military funerals year round at Arlington National Cemetery.