The WDW
DAS website pages still say:
”Please note that all park visits must be within 30 to 2 days of the live chat”
Some people have posted (recently) they were told they would need to call back to make DAS Advance Selections for the days that are more than 30 days out. Others were able to make them for all days of their trip, even the days that were greater than 30 days.
So, maybe, maybe not. But, if you complete the chat and are not able to do all the days, you can contact the DAS Advance Selection part of the chat and complete the missing days.