1. It predates the creation.
Soul King technically existed after creation, during the period of the Primordial World. You're seemingly talking about the current worlds within Bleach, and existing before them doesn't imply Soul King is conceptually independent from them, himself. His existence is fundamentally distinct from his title.
2. It is unchangeable. Concept of old and new doesn’t apply to this. Change of it would just mean annihilation of cosmos including current casuality system, laws since it would detroy everything and return to primordial world.
All of this just implies, at most, his title has instantiations of its existence being ontologically real. It doesn't imply said title is explicitly independent from the worlds it supports. You're presuming that if the realms are destroyed, Soul King's title would still have ontological power, and not just a normative description of himself. None of which has been proven.
3. It is not dependant on realities, space time. It's the other way.
You're just presuming this without due evidence. In the past, Soul King wasn't even called Soul King. His actual name is Adnyeus, and the title of Soul King came about after his dismemberment and crystallization. We have no reason to believe that Soul King; the title alone, is ontologically independent from Space and Time like a Platonic idea is. In actuality, it's seemingly the opposite, as it came about after the aforementioned ritual and creation of the world.
Existence of all of realities is literally dependent on this title.
But whatever
It's dependent on the power derived from the title, not the title alone. If that was the case, anyone who was described as Soul King would be able to fulfill the position. We know this to not be the case, so there is an additional factor to account for. I don't disagree with you that Soul King, as a title, is conceptually true, that is instantiated by several sources. I argued such in your thread. I disagree that Soul King himself, as an entity, is conceptual. There is a distinction between the two.
If you're just arguing the title alone, I retract the "it isn't even conceptual" claim from my original post. I still disagree with it being a Type 1 Concept though, as explained above.