ΔE 11.7, fair: the same colour family, but not a straight swap. Cultist Purple is a little darker, more saturated than Lavender.
Only where an exact match doesn’t matter, such as a new unit or a highlight. Fair match (ΔE 12). Cultist Purple is a little darker, more saturated than Lavender.
The same difference applies the other way round: Lavender is a little lighter, more muted.
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 Lavender on the colour wheel See Cultist Purple on the colour wheel
All matches: Lavender equivalents · Cultist Purple equivalents