I suspect they are also waiting for Trump to do things before opposing him. I have heard official Democrats rejecting the worst of Trump's appointments. It may be that they think their opposition will be more successful in gaining support if it seem as in response to Trump.
As to their calls during the election that democracy is at risk, I suspect they viewed that as very possible, but they are dealing with the fact that the majority of the country either did not think they were correct or worse did not see losing democracy as a negative.
I wonder if they themselves are trying to figure out any path we have to avoiding the worst. The fact is there is a far right SC, and the Republicans control the Presidency, the Senate and the House. I wonder if their current relatively low key opposition might be that in the House and Senate they are looking for Republican defectors on important issues. If they exist and when those issues arise, that might be the time to generate enough support for our position to make their rejection of the Trump extreme more likely.
I also suspect that after the entire Biden term of rejecting and legislation on things like immigration, they might support something like the bill Biden would have signed. Of course, they will claim theirs is entirely different and much better. A bipartisan bill may be needed on everything because the House majority coupled with the number of crazies.
I think the difference between our officials and theirs is that ours strongly believe in the need for government to work, while a large group of theirs are fine with inertia. Unfairly, this sometimes means that they pass things that were long worked on by us that they opposed for years like the criminal reform in the first term - a bill similar to things Durbin worked on for years.