Just winning every single Senate Race up for grabs next week would more than be enough.
FiveThirtyEight last I saw had the Democrats at a 51-49 lead after this election. Getting DC and US territories full representation would give the Democrats 2 more for DC. Puerto Rico might be a split. American Samoa, Guam, Northern Marina Islands, and Virgin Islands getting statehood probably might go as well as 7-1 Senators for Democrats. Now this is assuming they all want to be states which should absolutely be their decision. That only gets a 61-51 Senate split so not enough to kick someone off the Supreme Court. This would also change the old requirement that a territory have 60,000 residents before being granted statehood (Northern Marina Islands and American Samoa were both less than 10,000 short at last census).