Russia is demanding payment in rubles for its natural gas, not accepting dollars or euros from countries deemed "unfriendly". This move represents one of the most important financial news because it represents a significant step towards de-dollarization. This adds to the fact that Saudi Arabia is considering accepting yuan for the purchase of its oil by China.
If these 2 measures proceed, the status of the dollar as the world reserve currency would be hurt, trust in the dollar would diminish and more countries would not see the need to use dollars for international trade. the consequence of this could be devastating for the US economy and for the Western world in general since those economies are characterized by high debt.
For further information, read this article