The point of all that is Republicans have done very, very well at the state level - even if not so well at the Presidential or Senatorial levels.
The U.S. Constitution gives great latitude to States in determining how Congressional districts are computed so long as they meet certain tests including the "One Person, One Vote" rule that was established by the U.S. Supreme Court in the 1965 Reynolds v. Sims case.
According to the Legal Dictionary,
The Court ruled that a state's Apportionment plan for seats in both houses of a bicameral state legislature must allocate seats on a population basis so that the voting power of each voter be as equal as possible to that of any other voter.
Presidents and U.S. Senators don't draw Congressional District lines, state legislatures (for the most part) do.
Republicans have put a lot of time, effort, money and talent into state races and so they have earned the right to draw the CD lines in far more states than Democrats.
And, "elections," as my Democrat friends have been chanting for the past two weeks, "have consequences."