ΔE 36.8, loose: different enough that you should pick on purpose. Cygnar Blue Highlight is noticeably lighter, more muted, cooler than Magecast Magenta.
Not as a straight swap; see the closer alternatives below. Loose match (ΔE 37). Cygnar Blue Highlight is noticeably lighter, more muted, cooler than Magecast Magenta.
The same difference applies the other way round: Magecast Magenta is noticeably darker, more saturated, warmer.
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 Magecast Magenta on the colour wheel See Cygnar Blue Highlight on the colour wheel
All matches: Magecast Magenta equivalents · Cygnar Blue Highlight equivalents