The Queen's funeral will be a full state funeral so on objective terms, it will
be more extensive and elaborate.
The circumstances of the deaths were of course very different, and that impacted people's reaction.
Diana's death was untimely and tragic, leaving two young sons with her life being marred by a lack of contentment.... so people's reactions were more visceral and raw.
The Queen's death was very different... deeply sad, but not tragic. She was 96, and had a full life of unblemished dedication as Head of State. People are mourning an era, as well as a person. The grief is profound more than acute.
So yes, I think you're right to say Diana's death "touched more hearts" in the sense many were more emotionally impacted
due to the sheer unexpected tragedy of her death and its circumstances, but that doesn't mean Queen's funeral won't or shouldn't be bigger.