This recently released TV is on special at Harvey Norman for today only (likely matching The Good Guy's 15% deal: https://www.thegoodguys.com.au/sony-75-inches-x9500g-4k-uhd-…)
If you consider the gift card (and were going to buy other stuff from HN anyways) it brings the TV down to $4066.
It currently sells for $5799 at Sony's store: https://store.sony.com.au/television-4K-X9500/KD75X9500G.htm…
The differences between this model and the 2018 X9000F are very very minimal Comparison Here. You are better off buying the 2018 model from this deal here for roughly $1000 less
Newer isn't always better, some of the new RU 2019 TVs from Samsung are trash compared to 2018 (specifically the 8000 and the Q6)