This method does not need Nintendo Online subscription.
However, it will need a lot of patience. I prefer to only use this for a small amount of dates, but if you do not have a subscription, this is your only choice.
I recommend using touch screen for this.
5. Advance the day only by one, hit OK, then reenter the game
6. Now exit the raid lobby.
For however many days you have left, you gotta redo steps 1-6 for each day.
This method is pretty laborious, but if you're fast, you get down each day advancement to 5-6 seconds.
Edited by theSLAYER