What Democratic norms are being violated? There have been instances in the past where Presidents in this exact position filled Supreme Court seats. That is their constitutional duty. And the Senate is to provide advice and consent. There is not some Democratic Norm Rule that says that the left wing of this nation is guaranteed 4 seats on the Supreme Court, nor do outgoing Justices get any real say on whom or when their seat is filled. The Republicans are currently following the rules. You want to be pissed over Garland, have at it. We have had candidates Borked and Kavanaughed so getting lectured about gentlemanly behavior is ****ing laughable.
Now, you want to talk about breaking norms? Packing the court because you lost elections is breaking norms. Packing a court because an 80+ year old jurist, who could have retired when a Democrat would pick her replacement, rolled the dice and lost. Adding states to try and have additional Senators for team blue. That is breaking norms when you intend to do it by simple majority rule by ending the filibuster.
Don't put your willingness to start fudging rules because you cannot win enough elections on us. When rulings went against the right, they dug in for a decades long process to get to this point. You want abortion? Go vote on it in Congress like laws are supposed to be done. You know, the Democratic Norms you are bitching about.
Adding states and packing the court is what is outside the norms. You do that you might as well just split the country up now.