Deep strikes damaging Ukrainian infrastructure do not seem to be damaging the nation's resolve and I have no reason to believe that deep strikes into Russia would be any different. I cannot recall of a campaign where anything other than wholesale destruction, or the demonstrated prospect of wholesale destruction, has had a significant effect on the willingness of a people to continue a war.
In terms of effect, bleeding a nation of its young men and material, is more likely to bring on war weariness than direct attacks, which will only give a reason for resentment and a feeling that perhaps the losses were somehow justified after all.