Charlie: Impeaching Pompeo simply moves the Acting Presidency down the line to another Trump cabinet member.
The Justice Department can issue a legal opinion before January 20 that constitutionally the succession act must skip members of Congress. Then at noon on January 20 the AG swears into office as Acting President a member of Trump’s cabinet.
As I suggested, read “A Presidential Succession Nightmare”, written by a liberal Democrat legal scholar.
Once Pence is out of office, Republican Chuck Grassley becomes the presiding officer of the Joint Session of Congress in the absence of the joint session having yet declared a winner of the electoral college.