AlphaGo, LeelaZero and KataGo all agree that 7.5 is too much.
It seems that 6 - 7 komi is more fair than 7.5 komi under all rule sets. Why is the fact that 6.5 komi is about the same as 5.5 komi under Chinese rules, considered a stronger argument than fairness of komi?
(also see What is the "Strong bot based fair komi" for 19x19 using Japanese-like (for example, KataGo) rules - #7 by hexahedron stating that 6.5 komi may be fairest under Japanese rules and 7 komi may be fairest under Chinese rules, according to KataGo)