Least Sandpiper or Semipalmated Sandpiper? Washington, DC (1 Viewer)

[ExistingHuman]

I'm brand new to birding and saw this bird in Washington, DC a few days ago. My initial guess was that it's a Least Sandpiper but I posted on Reddit and got conflicting responses. One commenter thought it was a Least Sandpiper and the other thought it was a Semipalmated Sandpiper. Any thoughts? Both seem somewhat plausible based on the info on eBird, the Audubon site, etc. (Apologies for the low-quality videos.)

 

[Butty]

Bill too long and stout for least sandpiper. Thus presumably semipalmated sandpiper (though bill looks rather long for that too, suggesting western sandpiper but the dark chest looks wrong).