It's not really in my interest to tell you this, but this week's midterm elections are shaping up to be extremely normal, to the point of almost being boring.
The incumbent president is mildly unpopular, as incumbent presidents midway through their terms often are. His co-partisans in Congress are expected to lose seats, which is also not unusual in an off-year election.
You can read all the punditry you want — I hope you do, there's a lot of good stuff out there! — but any worthwhile analysis should acknowledge this baseline scenario.
That said, there are some idiosyncrasies to this year's election. Republicans have harmed their odds by nominating kooky characters in some races, and those characters do seem to be polling somewhat worse than more conventional nominees. Democrats are struggling with Hispanic voters, and there are signs the party is also slipping with Black voters.
Most voters are solid partisans. But elections are decided by the voters who aren't solid partisans — they agree with Democrats about some things and with Republicans about others.
When Democrats control Congress and the White House, they inevitably do some things that some of these cross-pressured voters don't like, and they turn to Republicans to counterbalance. When Republicans control Congress and the White House, the opposite happens.
Even the limited historical exceptions to the midterm backlash — in 1998 and 2002, say — occurred not only amid extraordinary events (impeachment and 9/11) but at a time when the president's party didn't control Congress.
It's certainly conceivable that President Joe Biden could have avoided the midterm curse of almost all the presidents before him (and it's possible he could still, I suppose, though it is extremely unlikely). If so, that would be a truly extraordinary outcome that cries out for explanation. What appears to be happening instead is extremely routine.