In order to complete All Dungeons, you have to complete all Main Quests. Also, timing is the same. If timing was changed to a segmented run of all dungeons, then it could be a category, but I think there is too much overlap between AMQ and AD.

You do not have to complete all main quests to complete All Dungeons, the memories are completely optional for example. All Main Quests also includes the Master Sword. This also includes more shrines in order to get the hearts for MS. The restrictions add a decent amount of time and gameplay to the speedrun, and definitely enough content to differentiate them.

Thats not true. All Main Quests includes all memories, the whole quest regarding Impa in Kakariko and the Hateno observatory, it also has the Fairy Fountain in it and the master sword, making several shrines necessary. The categories are vastly different and have completely different routes.

Just because one is only 50 minutes longer than the other doesn't mean they are the same.