Remember that the initial fall in oil price was a supply shock (Saudi Arabia upping production) that was only exacerbated by lack of demand. If demand comes back it won’t push oil back into the 50s/60s.
The saudis are losing money doing this (they have to eat into their reserves to fund the country). Russia at least has other industries, however small it may be.
Saudis cannot care less because they have about three times of Russia reserves nominally. In fact I suspect about five to seven times that, because Russia reserve structure is basically unknown. Saudis can certainly afford a year or three of having no income.
This is on top of the virus panic (which just cut any remaining tax revenues). Russia, Venezuela, Iran for that matter are done for.
EDIT: Which is why I think the whole OPEC+ deal went to the crapper. Middle East is able to weather this, others - not so much.
Arguably there isn't anyone like this in the rest of the world either, but I digress.