Hello friend greetings to you, hope you are doing well and good there.

You have beautifully explained all the layers of Blockchain. The graph you have drawn is amazing. You said that in Blockchain scalability is achieved through sharding process which is very much true.

sidechains and rollups are explained very well and yes these two are very much important for layer 3 blockchains. Your post is amazing dear friend, you have made a nice attempt.

I wish you very best of luck in this contest.