Another problem: what if you end the filibuster, make DC a state...and the Supreme Court declares it unconstitutional? There is constitutional law debate over DC qualifies to be a state or not. I would imagine the court, with the current conservative majority, might shytcan such a bill. Meaning the power play would blow up in your face.
Same applies to other things a democrat majority might pass, like universal healthcare. The way the court system is set up, it wouldn't be hard for right wing justices on lower courts to declare something unconstitutional and slowly get the case sent to the Supreme Court, where a 5-4 majority would side with them. So there are a lot of potential pit falls in place for this, to the point where I wouldn't criticize Biden for not going in this direction.
I could be wrong, but my understanding is that the judiciary can only rule on actions of the federal government that are currently taking place (and specifically, some party is claiming they're being harmed by those actions), or ruling on actual laws that are in force, and not bills that might become law some day. I can't see how they'd rule that DC statehood is unconstitutional before it actually happened.
Not to pick on your post, because I do think a conservative backlash is worth keeping in mind, but this does bring to mind something I've wondered about for a while now. How much do conservatives worry about how future changes in the political winds/electoral fortunes should guide their present political strategy? I'm admittedly ignorant on how much introspection and internal debate Republicans engage in when it comes to what a Democratic backlash to their policies might look like. But however much they engage in it, it doesn't seem to constrain what policies they pursue/enact. It seems like whenever they have power, they wield it to their own ends without regard for what the other side might think or react (probably because they don't think Democrats can legitimately wield power, but that's another topic).
On the other hand, Democrats seem to do so much handwringing about how Republicans will react to their policies, they come off as afraid to actually wield power. And it seems counter-productive. If Democrats are going to constantly hamstring themselves and the policies they push for worrying about the inevitable Republican backlash, then they give their supporters little reason to vote for them in the first place. That kind of worrying energy could be better put towards strategizing how to blunt the backlash (e.g. electoral reforms to reduce or eliminate a lot of the built-in advantages Republicans have given themselves in elections across the county) rather than trying to enact policies in a way that won't invoke a conservative backlash that's going to come no matter what.
Democrats need to actually wield power for their ends for a change.