While the Dems have gain somewhat in 2018 and 2020, I consider the wave to actually have been very Red.
Since 2008 and tea party has really shifted the Republicans you are seeing at the State and Federal levels. Boebert in Colorado is a good example. She replaced Tipton, a run of the mill Republican from 2010 that steadily shifted supporting Trump further and further, but it still wasn't enough to defeat the more radicalized Q-anon spouting gun rightest Boebert.
Locally, while we see notable Dem gains, the same shift has happened. When you look at McClintock, Moorlach (even though he lost to Min), Steel and then down to the Orange County level positions, they have steadily gotten more hardened, more extreme in anti-government sentiments.
As a moderate Republican, the party today, locally, nationally, is far more extreme in anti- mindset and operation than 10 years ago. Hawley of Missouri is a good example of a bizarre persecuted theocratic type view of entitlement that has taken hold.
Many of the Republicans today are the kind of people they are afraid AoC, Omar and squad are.