You need to store the vehicle with the fuel tank either completely full or completely empty and drained.
When using the car you need to occasionally ( every couple of months) run the tank down near empty less than a quarter tank then re fill it full.
With today’s fuels, if I was only driving the car enough to burn a tank full a year, I would be looking at installing some kind of small auxiliary gas tank in the trunk so that the gas would get used up and replenished on a regular basis.