They hold none of the three branches.
They can whine and protest, which they've been doing. Literally what else do you expect besides them to hold the country hostage via the debt ceiling or shutdown? (And, I might point out the Dems are in fact threatening a shutdown unless changes are made to ICE.)
Democrats have voted against almost every significant bill so far.
What would proposing bills do?
They've been doing the obstruction. You've forgotten Hakeem Jefferies' record setting filibuster because it doesn't make a lick of difference; "oh yay, the bill was stalled for two days! Mighty victory!"
The reality is that the Democrats are essentially powerless until the midterms and unfortunately, reality doesn't change because you wish it were otherwise.