Gift from grandparents, compulsory shares

Hello!
First of all - we are still at the very beginning of our considerations. If it comes to that, we will visit a notary anyway.

My grandparents (are partially cared for by us) have offered to make a gift and give us their house+property.
The house is quite small and in need of renovation. Since both still live there, an extension to the house or the conversion and extension of the outbuilding is an option.

If the grandparents make the gift to me as a grandchild, the three children (unless they waive their rights) must be paid out.
But what about the other three grandchildren? Do they also have a claim to a compulsory portion and if so, how much is it?

Would it then be more sensible to make the gift to Child 1 (in this case my parents) and then from them to me? Then Child 2+3 of the grandparents would be paid out + my brother.
Am I correct here?

Attention layman knowledge:

To my knowledge, there is no compulsory portion for grandchildren as long as there are still children.
A compulsory portion can only exist if the grandparents pass away; for now, it is just a gift.
Of course, it could also be a partial gift if you had to pay out all the children of your grandparents.

How a pre-gift to a non-inheriting grandchild looks in the event of death, I cannot say.

Where do the grandparents want to live then? Is a lifelong right of residence planned?

Furthermore, it should be examined whether gift tax might also result from this, since the tax exemptions between grandparents and grandchildren are lower than between parents and children. So, the first questions would be: what is the value of the property + house, and will a right of residence be registered or not.

You will have to see a notary anyway, as this concerns a real estate transaction. However, you will more likely receive advice from a lawyer.

The grandparents continue to live there and retain the right of residence. Later, it could be rented out or the children could move in.

The value will almost certainly remain below the exemption amount.

And gifts have (almost) nothing to do with inheritance. If the grandparents give you something during their lifetime, the estate is correspondingly smaller. Your exempt amount for inheritance is then reduced or not available if 10 years have not passed. The grandparents can give to whoever they want... no one has to be paid out. Grandchildren do have a compulsory portion entitlement but have no claim as long as the parents are still alive. To my knowledge, grandchildren can also be excluded. However, this would not be necessary concerning the gift.

The exemption for gifts is €200,000 (per grandparent to each grandchild). Together, therefore, a maximum of €400,000 per grandchild. You can only fully utilize this if the house belongs to both... Above that, gift tax is due.

As long as the grandparents are alive, they can do whatever they want with their money and property. The children would have no claim to it.

But get professional help.

The grandparents continue to live there and retain the right of residence.

This means the value of the gift, with the definition of the house as "small and in need of renovation," approaches zero (unless the grandparents are already very old). Otherwise, as my predecessors already said: a gift is not an inheritance!