Yes that is the most likely explanation - from Siberia to Americas and from Siberia to South Asia.
But that slight affinity to the AASI-related Ongee and also Denisovan in S. America has been a puzzle.
"An increasing body of archaeological and genomic evidence has hinted at the complex settlement process that likely occurred in the Americas, which is only now beginning to become unraveled. This is especially true of the peopling of South America, where archeological sites suggest humans reached the continent soon after the first migrations out of Beringia. However, unexpected ancestral signals (e.g., Australasian) have raised perplexing scenarios for the early migrations into different regions of the South American continent. Here we present ancient genomes from northeastern Brazilian archaeologically rich region, and compare them to ancient and present-day genomes throughout the Americas. We find a distinct relationship between Meso and South American populations, including ancient individuals from northeastern Brazil, Lagoa Santa, Uruguay and Panama.
We also find a strong Australasian signal in the ancient genomes near the Atlantic coast, likely originating from an unexpectedly high genomic affinity with present-day Onge. Together, these ancestral connections present genomic evidence for an ancient migration route along South America’s Atlantic coast. To further add to the complexity of peopling of the Americas,
we also detect greater Denisovan ancestry in ancient Uruguay and Panama individuals, than in ancient Brazil, suggesting multiple waves of ancestral migrations along the coast. This work sheds light on the deep demographic history of eastern South America and presents a starting point for future fine-scale investigations on the regional level."
https://www.ebi.ac.uk/ena/browser/view/PRJEB48809