To prove insurrection you would need to prove he made an attempt to overthrow the US government.
Not going to happen.
For espionage you would need to prove he actively worked with a foreign government to compromise the US government.
Again, not going to happen.
And once congress gets irrefutable evidence of the Biden's corruption the DOJ will no longer be able to protect Biden and will file charges, they will save their own skin first before his.
As for Trump, the best you can get him on for 1/6 would be the incitement of a riot and that's a longshot which is why charges haven't been filed yet.