The answer is you don’t
I couldn’t give less of a crap about powerscaling, but I care so much about the series that I eventually have to do it. Without Sukuna being able to basically no diff Gojo if he tries, it totally destroys his narrative of being an incomprehensible calamity who can win despite assigning himself several limitations to prove a point; without Kashimo losing to several characters in the way he does, the metaphor of an Edo era Samurai overestimating himself cannot work at all.
Essentially, you don’t do it for powerscaling, you powerscale for writing. If someone says to you “hey how does Sukuna beat Gojo this way or that way it looked extreme diff to me”, which TSD can say himself he had that opinion, I respond not because I’m a Sukuna glazer and want him to beat Gojo (I actually love Limitless WAYYY more than Shrine), but because I know Sukuna being able to do that is necessary for his character.