Only the casinos getting the 15 licenses gets decided by then(should be next month but there were 50+ registered bidders so might go longer). Some casinos are expected to leave the market in Dec, some will be allowed to stay. iirc its around June 2027 for stuff being actually put in place/enforced where stuff like autospins will be removed. It's still unclear on firm dates.
As players we are free to play on casinos outside of our country where no such restrictions are in place btw, shouldn't impact me significantly other than some big brands opting out of NZ if they don't win a license.