*Can* you be charged with treason other than in a state of war? I don't know much about US legal matters...
According to wiki, it looks like it-
Definition: In Article III, Section 3 of the United States Constitution, treason is specifically limited to levying war against the US, or adhering to their enemies, giving them aid and comfort...
... Levying war means the assembly of armed people to overthrow of the government or to resist its laws. Enemies are subjects of a foreign government that is in open hostility with the United States.
So I guess it could have been used against the Seattle insurrectionists. But most of those weren't prosecuted on account of them being 'peaceful protestors'. Such is US politics. Insurrection is also illegal, but despite media reporting, no charges. That might be easier to charge Epps with given video evidence of him encouraging crowds to 'storm' the Capitol. But for whatever reason, he doesn't seem to have been arrested or charged.
Stuff like this doesn't help either-
Online sleuths named two of the five agitators as Camden Layton, the finance director for Virginia Young Democrats, and Colleen Wachenfeld, another Virginia Democratic employee whose background on Twitter was a picture of McAuliffe at a campaign event.
Which seems a little odd given the DM refers to the Lincoln Project as "a group of anti-Trump Republicans"