Is there any distinction in your thinking in your first sentence between "real" and reality? I think we did admit a distinction above - I could be mistaken. If a tree-in-itself-as-it-is-in-itself, ding an sich selbst, is the reality, is "reality" interchangeable with "real"?
(What we see cannot be the tree itself - we see different trees - my image differs from your image!) I agree "the phenomenal is real" - just not reality, or at least not the reality of the tree. Maybe the reality of the perception of the tree. We just have to be careful about exactly what we're affirming. You've left out the steps between perceiving and learning - maybe that doesn't matter.
One reason I have gone to the phenomenal is its objective certainty. While we may be certainly wrong in what we perceive, we can't un-sense it, it may not be but it certainly can't be un-sensed. Descartes's point of certainty may be absolute but leaves us in a subjective waste land. The phenomenal , unlike the Cogito, can be shared. Did you see that cherry tree, yes it is beautiful I especially like it white blossoms against the stark gray background of early spring. Of course I could be feverish, delusional or tripping, but you can tell me that I am mistaken, and together we can work it out. Unlike the solipsistic nightmare of Descartes's certainty, shared phenomenally is objectively certain real. The certainty of the phenomenal is capable of being shared, corrected and enhanced.
I think an epistemological foundation is necessary and must be ascertained on an intersubjective level. If we believe Kant we can't know the "in itself" the objective, instead we determine the transcendental presumptions that are needed to account for our experience of the world . It is not really an ontology as such and I concur however I think the phenomenal realism I am thinking about has a transcendental character which based on its concurrence with others. Therefore it is both immanent (in the world) and transcendent (shared with others) at the same time in a shared world.
What we come to is "spirit as a social construction." Admitted and agreed: there certainly seems to be, e.g., national spirit. But this cannot be spirit in itself, can it? You've given an example, not the thing itself. If I look at your description, spirit seems to be the derived, the abstracted, the generalized, gelled into a being. If that's the case, then we have this, that, and the other thing called the spirit of this, that, and the other thing, but we have lost spirit itself, except as an entirely abstract collective term with no content in itself. The questions of the being and existence of spirit simply evaporate.
Spirit in itself is a dynamic whole, the affirmation all we have derived, learnt, remembered, shared. Its dynamism works in our life in concert with others...this is its affirmative effect I think. Spirit's construction starts on day 1 and never ends until we end. I don't think that Spirit, as a 'thing' is possible to demonstrate because it is constantly changing, only partial view points are possible.
It is only in and through our relationship with others that fragments of our spirit can be shared, imparted, and understood by us and others. Our relationship with others is cemented in language, where we can phenomenally share meanings.