I don’t think I would say that churches were becoming more impersonal. If we look at Christianity and Judaism throughout history, early churches and places of worship were sectioned off to where the most holy place of God was separate from the “common” place of the building. In the Gothic cathedrals, there is such a sense of openness and availability of being close to God, that this is almost the opposite of impersonal. Instead of having a relationship with God through the priest or pastor, God is available for personal relationships with this new architecture.
The fact that people would invest in private devotional objects is another key point to show how much more personal religion had become. We have moved away from the Bible only being in Latin, to the Bible being available to even those who were not literate. Just because churches and devotional spaces were becoming more ornate this does not necessarily mean it was becoming impersonal.