Ask Lemmygrad

as I would have to pay hefty taxes. Letting it stand empty does not make sense.

You can always rent it for a while and think better about your situation. Just selling it and putting the money in the bank just means the bank will be using your money to possibly cause way more damage than you could anyway. Buying shares, at least if you don't even work in the company is bad too, so holding on to the apartment is not the worst thing you could do and if you sold it it's possible the new owner would just rent it too.

If you rent you could always see if the person living there would like to buy it from you and so you can even give them a discount based on how long they lived there if you think it's better too.

and I’m planning to sell it in about 5 years when we’re gonna be looking for a new place with my parents.

If you already know when you need the money you can alway do the math and see what is the best option for you. Let the money stay in the bank, keep the apartment until them... And also check the risks, as in my country, as an example, the goverment has taken peoples savings about thirty years ago when the inflation was bad so who knows if they will do it again. So if you were in my country puting the money in savings would have an extra risk, while perhaps there might be countries where the goverment has made housing cheaper before and could do so again, meaning holding on to the house might not be the best idea either.