I am now on my second NX450h+ Premium Plus.
I've not had any issues with the 12v battery and I don't put it in ready when loading or anything else. Having had a problem with the 12v battery when I had a Mitsubishi Outlander Phev I bought and still carry a power pack. So far in nearly 2.5 years I've not had to use it. Note to self - must give it a charge 😁
On tyres, I was grateful for the run flat when I had a puncture on my way to visit my Dad in palliative care in hospital - it meant I didn't have to get dirty changing the tyre, or hang about for the roadside assistance, as time was of the essence that day!
The next day I took the car to Lexus Leeds and they fitted a new tyre from stock. The original wasn't repairable. This was Feb '24.
In April I had a puncture (on the new car) and I got that repaired at my local tyre place.
I've taken out the Lexus Tyre & Alloy insurance on both cars and it has been an easy claim process (but read & followed the instructions before getting the tyre changed/repaired!)