The church finds evidence? The church is made of MAN. Man CANNOT state who is a saint and who isn't. MAN CANNOT look into the heart of another. That is God's job.
The evidence that theChurch is looking for is whether the proposed saint left any teaching, writings, acts, and if so are they consistent with the Church’t teaching. It then looks into miracles that the saint worked. This is all forensic work that reasonable people can do, and they are not in a hurry to do it.