The point of Xykon and his level, since that character got first introduced, was that he is of such a high level that it simply does not matter anymore what it is. 25 or 55 who cares? He is not the enemy you defeat by punching him. He's the Big Bad and the End of All Things.
Xykon is the worst thing that could happen and he's nigh undefeatable.
That is the point of such a powerful enemy. Compare him to the Emperor of Star Wars. He has such massive amount of power that it simply does not matter anymore to quantise it any meaningful way.
You fight him straight on? You lose.
There are some enemies against which you simply cannot do anything at all. Xykon is one of such.
The story that The Giant tells here is going to end up a big win because the Order is against a foe that is so powerful that cannot be, by any measure, be beaten - but they still will have managed somehow (paying a high prize in the process as well, probably).
It's how "High End Enemies" and stories with them as Villains work.
So I suggest to simply stop bothering those questions you just asked.