Packing the Court has been a leftist dream going back to FDR. That is more true than ever right now. While Ketanji "Biden's Brown Sugar" Jackson is a leftist, she is just replacing another leftist and that leaves the court with a 6-3 "conservative" majority. That majority is poised to do some stuff like overturn Roe v Wade/Casey v Planed Parenthood and strengthen 2nd Amendment protections.
You probably didn't hear about the Presidential Commission on the Supreme Court but it released a report in December and reading between the lines it is providing a framework to add Justices to the SCOTUS, under a Democrat admin of course, thereby undoing the "conservative" majority and giving carte blanche to the Left to run wild, either by allowing legislative and executive overreach to remain unchallenged or by simply making up laws like abortion on demand and "gay marriage" out of whole cloth.
Right now the Left is in disarray. Biden is unravelling more every day and is incredibly unpopular, especially impressive since he hasn't actually done anything other than undoing some stuff Trump did. They are clueless what to do about Putin so they aren't doing anything. At least doing the wrong thing loudly and proudly would be something but they are just looking around befuddled even though they have been talking about this for months. The looming election cycle is looking like a disaster for the Left but never underestimate the evil of the Left and the stupidity of the "Right". There is plenty of time to fuck this up. Besides what would be different if the GOP has a huge victory in November other than things going badly a little more slowly? They mostly seem to be threatening to hold a bunch of useless hearings, that should get the voters fired up.
If the Left manages to pull off a win in November against the odds, something quite possible, don't think for a second that that they have not been working behind the scenes to prepare to take advantage. Biden is a dolt but there are plenty of evil and smart people who are pulling his strings. One of the pillars of their strategy is to pack the SCOTUS to give them a free hand to do what they want. Right now that 6-3 majority is the biggest obstacle in their path, not surprisingly because that is precisely what the SCOTUS and the third branch of government was intended to do, separation of powers and all that.
Don't get too distracted by the latest shiny object dangled in front of us, in this case Ukraine. The real war is not being fought in Eastern Europe but right here at home, in the shadows, and we are losing ground every day.