If you want to talk about policies, it changed in 2020 - see the link below. While noting that not all immigration offices do this, Chiang Mai Immigration does - at CM Immigration, you don't need to file a new TM30 when you've been out of the country and are returning to the same address, as long as it's not a new visa.
Other than you're a Kiwi, I can't work out much about you. But I can tell you this - real estate doesn't work the same here in the Land of Smiles as it does in NZ and Aus. Tread with severe caution and whatever you do, don't invest in Phuket.