color palette vs bitsPerPixel vs pixelFormat

According to https://developer.garmin.com/connect-iq/user-experience-guidelines/incorporating-the-visual-design-and-product-personalities/ most MIP displays have 64 color palette (except fr45, fr55 with only 8 colors)

However when I look at the SDK devices' compiler.json I see that for older MIP devices it has the color palette, i.e: fr245: palette.colors: [64 colors...], but newer MIP devices don't have a palette, i.e: fenix7, fr255: there's no palette in the file. The only related info seems to be: bitsPerPixel: 8, and the cryptic: pixelFormat: "ARGB2222"

, fr955So what colors can I use on these devices: fenix7*, fr255*, fr955? Is it only the same 64 color palette from the above link, or can we really access the 8 bits per pixel, and if yes how exactly? I mean which bits from FFFFFF can I use without "falling back" to some similar but different color?