2.3l-150 Multijet: Change timing belts or not?

I bought a used Pössl mobile home (box car) with Maxi chassis and 2.3L Multijet – 148PS. It was built in 2013 and only had a real 2000km down (I was able to verify by hand TÜV reports and gas tests). The car was bought again by the previous owner in 2013 and used once. After that it stood in a carport and was driven only to the all-possible TÜV and gas tests. The engine looks like fresh from the factory, no blooms etc., all steel parts still have d the original varnishes and have no rust. So the mileage is real. However, the colleague never had a customer service (what a miracle, with the low mileage). I have now transferred the vehicle home (500km) and have also handled it accordingly carefully. I would say that the engine has not really entered yet. So now he has at present just 2500km on it. First of all I want to make an oil/filter change of course, because I z to assume that even modern engines have increased abrasion at the beginning, which should be removed quickly with the oil and on the other hand do not know whether and how oil ages when a vehicle is standing longer. However, I have already been approached twice independently of each other from different points of view, because I should have the timing belt changed for safety reasons. Now a belt like this lasts at least 60000km, usually much longer. So I thought rather about having it still inside the belt. I was told, however, that a timing belt is also aging without it running and that 8 years are the point where a timing belt should be out regardless of the running performance. Is that so right that the aging of the timing belt material in the stand is so exorbitant that it has to be out after 8 years? Then you would have to have the time, the time, the timing belt, the timing belt material in the stand is so exorbitant that it has to be out after 8 years? he has already been in some spare part warehouse, pulling off and doing so, afaik nobody. Up to now I had never thought about timing belts and had them changed only after mileage, but mostly rather than prescribed by the manufacturer. So what to do? Let it go and switch in one or two years or out immediately?