I don't think there's a lot of good data, because it's hard to determine exactly how many votes may have been swayed.
I would again point to the two recent examples of Moldova and Romania. We know Russian-linked money essentially bought over 100,000 Moldovan votes in their recent election. Russian money and influence operations also caused the rise of a Romanian far-right candidate. He went from literally nothing—polling within the margin of being statistically insignificant—to over 22%, winning the first round of the Romanian presidential election.