I know what each part of the Mural means in "Serious Steven" well let's go.
The bottom three parts symbolize the traps Steven and Garnet had to go through. Well, all three are the same as in the episode, in fact the gems that are in these traps is a representation of what will happen to the intruders who enter the inverted pyramid,
The human hands can represent two things or the gem that is represented is attacking the humans although the other thing is that it is kidnapping the younger humans for the Zoo.
The central and upper part where Rose is fighting and the gems that are seen in the mural in addition to her are not the Diamonds as many would believe and it is one of the corrupted gems seen in the Steven Universe art book of End on an Era, and the same one that bubbled up in the same chapter where the pyramid and the mural appear
The name of the gem is Albite and it appears to be a high status gem from the White Diamond court.
And the things that are behind Rose is her Army since they are next to her. Which means that Rose and Albite had a fight sometime during the war either because Albite was sent by White to find more humans for the Zoo or because Albite tried to attack the humans, Rose attacked her with her army and Albite was defeated. and apparently Rose left her on that statue seen in Serius Steven.
