Voice in a text is practically point of view. So, the point of view from a certain character in a text is the text's voice, or the perspective that the author wants to present us with.
Well, for a correct sentence you would go for, "My Grandmother, God rest her soul, was the best cook and baker I knew."
I would think that comma would be the best punctuation. Hope this helps!
Answer:
Transcendentalists advocated the idea a personal knowledge of God, believing that no intermediary was needed for spiritual insight. They embraced idealism, focusing on nature and opposing materialism.
I really hope this helps you!
Have a great rest of your day! :)