We have:
King Toji himself prominently in the middle.
Female Toji
Toji's son (which gege hates because he wishes he is Toji's son)
Toji's fanboy (also gege's self insert)
Toji's pet (aka doraemon pocket dimension)
This is why Mai and Naobito is not there. They aren't directly associated wity Toji (not as much)
This is taken from his afterword and comment in the vol 3 Modulo extra.
Unlike his afterword in vol 30 of OG jjk where he mentioned about doing better for his next work. He now alludes to Modulo being his final milestone.
People basically treat him as an emotionless sorcerer and tool first instead of the human he is. And Megumi is one of the most human and in depth character in the manga. He had a very understandable reactions. Especially when it was sukuna (the strongest jujutsu satan in history) we were talking about which caused and inflicted all that to a 15 years old boy.
Especially considering that gege (through Maki) doubled down the fact that it was not Megumi's fault (see page 2).