What you are taking as ‘church’ in 1Tim 3:15 is really “synogogue,” not the complete body of believers.
Utter nonsense.
In I Tim 3:15 the word church in the phrase “church of hte living God” is ‘ekklesia’ the standard word for church in the New Testament.
If St. Paul had meant ‘synagogue’, that is itself a Greek word.
It it the Church of the living God which is the pillar and the ground of the truth.