I am predicting a little over 4M, since I think the holiday will be weaker than 2022 and 2019. However this year results till now were unexpected for pretty much everyone, including the biggest fans of the system, so everything is possible.
My sales comparison threads:
Ultimate Showdowns: JP 2023 / JP 2024 / 2024 / 2023 / 2022 / 2021
Lifetime Showdown / Historical Showdown / YOY Charts / 140M+ Club Chart / Quantity of Games