Can you enumerate some of the things that they could do, given recent actions have all been Executive Orders, which is the prerogative of the Executive branch.
Unless things start happening in the legislature, where perhaps things like filibustering are an option, what options do the Democrats have against purely Executive actions?
Biden had a very long time to do a lot of things. You can get a lot done with a bit of creativity and a willingness to cause a few constitutional crisis'.
There is no "opposition" power structure in the US system.
If congress brings a bill to a vote, democrats can threaten to filibuster it, but the GOP can pretty easily call that bluff right now.
That's it. That's the only "power" a minority party has in the US system.