The budget is in rubles and the exports are in dollars.
The exporters’ operational costs are in rubles too.
The lower the ruble rate the more is leftover income for the companies and taxable operations volume in rubles per same dollar sales which also eliminates the budget deficit for the government.
It also props national manufacturing and agriculture, getting a cost and price advantage over imports.
There are collateral damage of course, in form of inflation and the savers are getting screwed too.
Savers with accounts denominated in other currency actually get additional appreciation, so I’m not sure what you mean.