This budget is decidedly propaganda, based on falsified information. There are so many hidden deficits the real number is way way higher.
For instance weapons purchased by the government are bough at a loss for the companies supplying them. This loss is supposed to be covered by exports, but because the exports are down, they are instead covered by bank loans.
Russia is using every trick they can to make things look better than they are and hide the true costs. What would be interesting would be some analyst with good insight analyze what the probably real number is.

My guess is there would be so many uncertainties it would conclude between 20-50% deficit. Or to put it another way 35% ± 15.

According to whom? Russia?