It will be Manchin and a few other Dems that will never let the crazy stuff pass. Think of Rand Paul on the Republican side who blocked a lot of stuff.
Like I said. There won't be any Green New Deal or environmental crazy stuff that passes. Neither will defunding of cops because all that stuff is way outside the mainstream. But what WILL GET PASSED is that taxes are going up, especially corporate. Manchin or not, that will happen. Also, any kind of tariff against China will be lifted on Jan 21.
To me, the 50-50 stuff are things like the Wall. Hopefully Biden lets the construction continue. He hinted already that he will in order to stop a mass refugee exodus that might happen if the Mexicans think they can just hop across the border so easily.