thanks a lot @Niki for the informative link and information, i didn't know the "flat stopper" solution existed, there are other points in the link that is quite interesting to consider as well.
i am mostly concerned about the tyres, all what i could get in terms of ideas is either lift the whole car over jack stands, or use the flat stopper or of course the best solution which is to have someone to drive it every week or so if you can find this volunteer and in our case they need to do this for 2 cars so... 😁.
@Islam Soliman, as far as i understood the issue rises because the tyres resting on hard ground at a single spot for a long time, this spot start to flatten and some type of deformation occurs to the rubber, apparently this deformation sometime it is temporary as soon as you start driving the car again, other times it is just permanent depending on the size and duration i guess, (as a pure speculation from my side not depending on any solid information 😃) theoretically those flat stoppers allow the tyres to keep its circular shape instead of letting the tyres take the flat shape of the solid ground.
just crossed my mind, an out of the box idea yet not applicable, to park the car on the sand, soft enough will not harm the tyres 😂.
i just realized because of the Covid, a lot of people haven't been back their home countries for a long time so when they plan to go they stay there for a long time as well, and the flexible teleworking model that have been implemented almost everywhere, made it easier for people to work anywhere for some time, which brings another idea, why not make a business that provides a service that someone will take the car for a ride and a wash every week, i know i am willing to pay for that😉.
@Frederic, guess the inflating solution could work theoretically but the tyres tend to slowly deflate after quite some time, not sure if it could reach the point of getting the flat spot though?!