The real danger will be getting blamed for the likely Trump-created economic crash.
This. With the yield curve getting closer and closer to inverting, along with the other signs, it looks like we're not too far out from another recession. This has been a major problem for Democrats in recent history. Bush's tax cuts and putting a war on the credit card played a major role in the 2007 recession, but because things didn't really start looking bad for the average American until Obama was in office, guess who got blamed? And of course Trump is taking credit for the hard work done by Democrats to right the economy, though the tax cuts he and Congress came up with will be nothing but bad for the economy long-term.
That said, I do also agree with this:
I can't speak on behalf of every Democrat here, but I can tell you that I want Democrats to take the House not because I have any hope they will pass progressive legislation, but so they can investigate Trump and his administration. God knows this country needs Democrats in control of at least one house of Congress to keep Trump and the ruling Republicans in check, and have it actually fulfill its constitutional role.
I'm losing hope that enough people will turn out to vote in a way that actually makes this happen, but I hope to God it does. Our democracy is falling apart and we need someone to fight for it, even if that fighting is little more than futile.