Nice try, but "pillar and ground of truth" is referring to the subject "church", not "living God" in the prepositional phrase "of the living God".
I had not heard before of the "living God" being understood as being what "pillar and ground of truth" refers to, but that this verse teaches that the church is supreme over Scripture - which is what it is often invoked for - is more than what "ekklēsia zaō theos stulos kai hedraiōma ho/hē/to alētheia" states.
Scripture often uses words that essentially mean the same thing (faith confidence, etc.), and both stulos and hedraiōma essentially convey support, and the house of God is identified as being the church of the living God, which supports the truth, and is grounded in it.
The fact is that the Lord and His apostles and thus the church established their truth claims upon Scriptural substantiation in dissent from those who sat in the seat of Moses over Israel, the instruments and stewards of Divine revelation and inheritors of the promises, (Mt. 23:2; Rm. 3:2; 9:4) but which does render such assuredly infallible as per Rome, and superior in authority to Scripture, which is what Rome effectively claims (though i know you are Orthodox).
JESUS IS TRUTH! HIS CHURCH is HIS BODY.
Jesus is The Word and IT is ALIVE and ACTIVE.