Some political scientists with very strict definitions of the term say around 7% of possible voters, but others that include casual voters into the swing voter category have the number as high as 30% of possible voters.How much % of votes are swing voters? Significant?
Either way, yes, the number is significant enough to change an election.
Considering Biden already beat Trump once, obviously, any more swing voters breaking toward Biden because of these indictments and trials just makes things even worse for Trump.