Manchin and Sinema support DC statehood, so just make DC a state to minimize their votes.
The problem is that even if Manchin and Sinema support it, DC statehood can't happen while there's still a filibuster.
They can do like McConnell did with Supreme Court justices and specifically exclude the filibuster from applying to the admission of new states.
Or they could put it in the reconciliation bill and overrule the parliamentarian on a simple majority vote.
DC statehood is a 100% lock to happen if all 50 Democrats want it to, and it doesn't require complete abolition of the filibuster.