Why isn’t the character in line of succession to Holy Roman Empire

Context

I am playing as Duke of Austria currently.

The scenario is, My character's grandmother married her cousin who was Duke of Upper Burgundy. Since both were of the same dynasty, I didn't do a matrilineal marriage.

That cousin got elected as Holy Roman Emperor in a couple of year. They had a daughter after which the duchess of Austria (The grandmother) died and the title passed to the couple's only daughter.

That daughter (The mother of my current character) was the eldest daughter of the Emperor. Emperor remarried and had several kids including a son. He later changed the succession law of the Empire to Agnatic Primogeniture which made his only son the heir to the Empire.

Later the daughter died and my current character (Of the same dynasty as the Emperor, his grandfather) inherited duchy of Austria.

Issue

I was surprised to see that my character wasn't in line of the succession at all despite being the male eldest grandchild of the Emperor and belonging to the same dynasty.

The line of succession has the Emperor's only son on first position and includes even the Emperor's nephews from his younger brother who married a duchess of another dynasty matrilineally, in number two and three.

The game wiki says that Agnatic succession means that only males can inherit. I am male so what's the problem? The fact that my character is descended from female line of the Kaiser?

Question

Does choosing agnatic primogeniture disqualifies even the male descendants of a female from succession even if they belong to the same dynasty?

Why are the nephews of my character's grandfather included in the line of succession even though they are not even of the same dynasty?

Shouldn't my character be in the line given that:

1. He is the eldest male grandchild of the emperor.
2. He belongs to the Kaiser's dynasty.
3. He's elder than the nephews of the Kaiser.