Rear suspension travel is 215mm. Front is 220mm.
Rider sag = ⅓ travel so 70mm is whaat you are looking for on the rear. If you can't achieve this and your preload is maxed out - then time for stiffer springs, and maybe a re-valve to work better with the new springs. Best is proper rider sag - you on the bike in full gear with ½ tank of gas - with minimum preload.
I was mistaken. The app information showed SAG adjustment, but that is only for motocross models. The app will add navigation features for the Norden 901. Here is more info: Ride Husqvarna Application Information