In the sentence, "Let's continue to cherish what we have and create more beautiful memories together as a family," the word "more" implies additional beautiful memories, rather than a comparison. Here, "more" is used to suggest adding to the existing memories rather than comparing the new memories to previous ones.
However, there’s a slight nuance: by saying "more beautiful memories," it implies a continuity or building upon previous positive experiences. So, while it primarily means "additional," it can carry a subtle undertone of adding to or enhancing the collection of memories.