The Congress is made up of two chambers, the house and senate. The House of Representatives is up for re-election every two years. Members of the Senate serve staggered 6-year terms, not the House of Representatives.

"Technically just about every Republican that could be evicted was"
That is incorrect. Before the election there were 230+ Republican House members. After the election there are around 196. All 230+ memebers were up for re-election. Not just 1/3. That's the Senate you're thinking of.