ΔE 15.9, loose: different enough that you should pick on purpose. Sunrise Blue is a little lighter, much more saturated than Ulthuan Grey.
Not as a straight swap; see the closer alternatives below. Loose match (ΔE 16). Sunrise Blue is a little lighter, much more saturated than Ulthuan Grey.
The same difference applies the other way round: Ulthuan Grey is a little darker, much 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 Ulthuan Grey on the colour wheel See Sunrise Blue on the colour wheel
All matches: Ulthuan Grey equivalents · Sunrise Blue equivalents