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.
In this case, Joe Biden didn't have a high approval rating, and so the party lost seats. The reason they lost seats is directly related to the approval ratings. If the Democrats had done a better job they might have been able to win seats and keep the House. The blame is directly with the Democrats on this. Previous presidents have been able to gain seats for their party during the midterm, but required high approval ratings.
If any of the arguments here are "oh, I KNEW we didn't have good approval ratings and wouldn't do well, but..." then this is just conceding the loss, are admitting to being a loser, and are now trying to mitigate it. Democrats should have clearly done a better job and worked towards better approval ratings so that they could actually win seats. Starting the conversation with a contrived scenario where Democrats losing is the expected baseline is clearly just a coping method to justify the loss.