My house is new construction... could I be getting dirty sock syndrome... if so are the uv lights the way to go... smell is mostly concentrated where the return vent is

I need more info to give you any help. How new is the house? One or two story and where is the return vent, you should have several. Do they all smel or just one? Never actually heard the term dirty sock syndrome, tell me more.

House Is 6 Months Old
One Story
One Return In Hallway
Smell Seems To Be Coming From This Return Vent Where You Change Out The Air Filter
P Trap Is Full... So That Is Not It...
Just Don't Know
Stinks Like A Dried P Trap.. To Me But Builder Checked That And Said Nope, Not Dry
Said It Could Be Mold On My Coils... From Condensation... There For A Dirty Sock Smelll
Could This Be Happening In Such A New House, If Not What Else Could It Be

It is unusual to be able to smell anything near a single return because the air is moving so fast. Any how, smells like a dry p trap so lets check the attic to insure the vent pipe go through the roof, not just into the attic. Mold does smell bad but is is not like a dried out trap. We know what that smells like.