The standard of "substantial similarity" in copyright law depends not on how an expert would see things, but on how a reasonable average person would see things. Juries are not perfect, but a jury of random people is probably the most qualified way to determine the question "would average people see these two things as substantially the same."

Leonard French—a YouTuber and actual copyright attorney—does a good job covering the legal standards and issues here: https://youtu.be/t-tsw6Z4eHc.