Are you sure about that? There are two different rewards: there is “Preview Week” and “2024 Beta: Wave 1”. With the later one sounding like it will be earlier than 1 week before early access.

Edit: from their Kickstarter:

DISCLAIMER: Recipients of the “Preview Week” reward will gain access to the beta playtest approximately one week prior to Early Access launch. Recipients of the “2024 Beta: Wave 1” reward are expected to gain access to the beta playtest in February 2024.