The question of the constitutionality of the impeachment trial should be settled. 56-44 was the vote that said the trial is constitutional.
Like a law being passed by a legislature, all should adhere to the law. You can’t say you won’t obey a law just because you don’t agree with it.
In that same vein, the 44 Senators should not use their disagreement with that vote as an excuse to vote not guilty. They should now abide by group consensus and decide their vote just on the facts. If they do not, then they will not be adhering to their oath to be impartial jurors. If they persist in denying the right to hold the trial, they are too biased and should recuse themselves.
If they do not recuse themselves and still vote not guilty on the basis of the constitutional grounds, they should be censured and/or expelled. If neither occurs they should be voted out of office.