ΔE 17.7, loose: different enough that you should pick on purpose. Cultist Purple is a little lighter, much more saturated, warmer than Twilight Purple.
Not as a straight swap; see the closer alternatives below. Loose match (ΔE 18). Cultist Purple is a little lighter, much more saturated, warmer than Twilight Purple.
The same difference applies the other way round: Twilight Purple is a little darker, much more muted, cooler.
ΔE is the colour difference between our two swatch estimates: under about 6 is close, over about 15 is loose. Real paints also differ in finish, coverage and how they thin, so test before you commit.
See Twilight Purple on the colour wheel See Cultist Purple on the colour wheel
All matches: Twilight Purple equivalents · Cultist Purple equivalents