https://archive.is/2023.04.18-152454/https://www.bloomberg.com/news/articles/2023-04-18/de-dollarization-is-happening-at-a-stunning-pace-jen-says?leadSource=uverify%20wall
The greenback’s share in global reserves slid last year at 10 times the average speed of the past two decades as a number of countries looked for alternatives after Russia’s invasion of Ukraine triggered sanctions, Jen and his Eurizon SLJ Capital Ltd. colleague Joana Freire wrote in a note. Adjusting for exchange rate movements, the dollar has lost about 11% of its market share since 2016 and double that amount since 2008, they said.
“The dollar suffered a stunning collapse in 2022 in its market share as a reserve currency, presumably due to its muscular use of sanctions,” Jen and Freire wrote. “Exceptional actions taken by the US and its allies against Russia have startled large reserve-holding countries,” most of which are emerging economies from the so-called Global South, they said.
I don't think it's necessarily about worries of immediate US sanctions, the drop might just be due to another major energy supplier no longer being able to trade in USD. Like seems kind of silly to go "you can no longet buy a large chunk of oil and natural gas in USD" then do a :shocked-pikachu: when people keep less USD on hand.