The dollar was strengthening until about 6 months ago. Since then it has declined 10% versus the Euro. The net effect, since February 24, 2022, is that the dollar is about 2% stronger since the start of the war.
Both the dollar and ruble are pieces of paper with ink on them the value of which is determined by imagination of counterparties.
Oil’s value is measured in joules, and there is no imagination involved. Very much like food. The calories are not determined by imagination.