14th Amendment, section 2 says:

Representatives shall be apportioned among the several states according to their respective numbers, counting the whole number of persons in each state, excluding Indians not taxed. But when the right to vote at any election for the choice of electors for President and Vice President of the United States, Representatives in Congress, the executive and judicial officers of a state, or the members of the legislature thereof, is denied to any of the male inhabitants of such state, being twenty-one years of age, and citizens of the United States, or in any way abridged, except for participation in rebellion, or other crime, the basis of representation therein shall be reduced in the proportion which the number of such male citizens shall bear to the whole number of male citizens twenty-one years of age in such state.

This means that if these states successfully pass legislation to remove Trump from the ballot when he is not otherwise disqualified from running, their congressional representation will be reduced by the number of seats proportionate to the number of male citizens 21 years of age or older who were unable or prevented from voting for that candidate's electors. There is no provision for removing that reduction in congressional power. States trying to remove the right to vote for Trump is a very serious thing and could permanently reduce blue states power in elections.