What does swing state mean?
Do you mean when you think it'll swing to the Democrats?
Or do you mean when will it be competitive?
If the former, then probably 2028 - 2032
If the latter, then 2024
By the general definition of the term, when both Democratic and Republican candidates get roughly similar levels of support among voters. Georgia and Arizona being the most recent examples.
Then 2024 (even if Democrats don't win I expect the margin there to be competitive and for both sides to receive roughly similar levels of support among voters, probably less than a 5% margin)
Why rule it out entirely?