Have a glance at history for a moment. You aren't making the strong case that you seem to think you are. Remember, history is only an internet search away!
https://www.presidency.ucsb.edu/statistics/data/seats-congress-gainedlost-the-presidents-party-mid-term-elections
Yes, I posted that link on the last page. That page shows that number of seats an incumbent president's party wins during the midterms is directly related to the president's approval numbers. According to that page George W. Bush and Bill Clinton had terms where their approval numbers were at 65 or above, and so their parties gained seats during the midterms. During one of Bill Clinton's terms he dipped in approval to 48 near the midterms, and his party lost seats in that one. During one of George W. Bush's terms he had an approval of 37, and likewise lost seats. Obama had approval numbers in the 40's during both his terms for his midterms, so his party lost seats in each instance. There is a direct correlation to this relationship.
The neat thing is, if you go back and look at that page and just scroll up a little bit from where you seem to have gotten lost, there's a whole bunch more data. Take a peek. You might notice a thing that happens in midterms normally. And you might also notice that the Dems did pretty well in this midterm when viewed against the entire history of midterm elections in the US. And, as was pointed out, they also did better than most when viewed against the last 20 years of midterms. So that's history viewed through both from afar (at least in US terms, we aren't that old of a country) and when viewed over a much shorter timeframe.
"We'll probably get more than 52 seats"
womp womp"It's gonna be a red wave"
womp womp"It's not gonna be a red wave, it's gonna be a red tsunami!"
womp wompHow'd the Arizona senate race go? What about Kari Lake's bid for governor? When is Don Bolduc getting sworn in? Dr. Oz? These folks were shoe-ins, after all, right?
womp womp