I can`t agree with this idea, I think Russia`s economy is rather strong, as they feel good even with all those sanctions they got from the US and EU.
Nope, Russian Ruble is slowly inflating. The corruption in Putin's administration is the reason for that problem. The reason that they only get by is because they are a nuclear super power. Not to mention that Russia is weapons dealer too, they also have connections to oil barons in the Middle East and China's trade relations with them is what is keeping them alive, not to mention the cyber attacks conducted by their hackers are generating money for their country too. It only looks strong because people can't outright complain about something because they knew that Putin crushes everyone that tries to expose his propaganda campaign, if you believe otherwise, then how come he wants Navalny and many other Putin administration opposition arrested.
If other states stop buying oil and gas from Russia, and buy an alternative in the Middle East or the United States, then Russia will have even more problems, since this country has no other sources to fill its budget, as well as to maintain the Russian ruble.