People said that the feng shui of my ancestral grave was not good, so they filled it in.

I don't know if you used the wrong word. Generally speaking, "filling the grave" does not mean "adding the grave", but going to the grave. If it is "filling the grave", it is equivalent to destroying the grave.

The feng shui of ancestral graves is not good, depending on what is abnormal in your specific embodiment (or performance). If it is basically normal, don't make a fuss in the ancestral grave, especially if you can't break ground easily. This is the taboo of ancestral graves.