ΔE 17.1, loose: different enough that you should pick on purpose. Gypsum White is noticeably darker than Praxeti White.
Can I use Gypsum White instead of Praxeti White?
Not as a straight swap; see the closer alternatives below. Loose match (ΔE 17). Gypsum White is noticeably darker than Praxeti White.
Can I use Praxeti White instead of Gypsum White?
The same difference applies the other way round: Praxeti White is noticeably lighter.
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.