If you absolutely HAVE to do a virtual tour and have no way to come in person, insist on being shown the units that are vacant and ready for move-in, not the model as others have suggested. Since your time frame for when you expect to move to DC sounds like it's relatively soon, you should be able to be shown the unit(s) that you are looking at for particular floor plan types.

But also, you definitely won't be able to get a gauge if important things like: is this flimsy ass construction? How annoying could the sound of the freeway right by the building possibly be during rush hour? Will I hear every conversation my neighbors next door make? Can I tell every time my upstairs neighbor drags their chair across the floor to sit up/down?

things like that the person conducting the virtual tour (by virtual tour I'm assuming you mean when they facetime/zoom/video call you whilst the leasing agent walks through the building) will all too conveniently mask with the sound of them talking or their shoes clacking on the floor every single time 😂