People said that about reddit, I don't think Lemmy is anywhere near being too complex for the average user. More that social medias generally favor simplicity because simplicity is easy to control, modify, and generally nudge from a developer side trying to guarantee a very specific use case that generates money, rather than just naturally occurring social systems.

Let's be real, humans have been dealing with social networks far more complex, systems more complex, for almost all of human history. The sheer volume of people, no, but the actual processes of interaction, yes.