Manga

I can't recommend colour e-ink. I tried it with already the expectation that it won't be great, but still got disappointed. I went back to my black and white e-reader. The colours are bad and it makes the actual b/w e-ink look worse:

• the colours have half the amount of pixels as the e-ink, making things look very jagged.
• colours have a very limited range (causing a lot banding like it's very compressed among other things)
• if there's a colour that takes up the majority of the screen (sky BGs for example), the rest of the image also gets slightly tinted that way.
• the colour layer (which is a tft lcd layer) on top of the b/w e-ink darkens the b/w. Meaning that unlike b/w e-ink, you always need the backlight, even in the bright sun. Even with the backlight on I found it always looking a bit dim.
• the pixels of the colour layer makes the b/w e-ink look pixelated, even if the colours are off. I could always see the tft layer, even when not in use.
• the screen looks nothing like paper anymore, even in just b/w

By getting colour e-ink just for the occassional colour page in LNs or manga, you'd be sacrificing all the black and white pages, while not getting a good colour page anyway. They all use the same screens too, so checking out multiple brands doesn't matter.

As for recommendations, I use a b/w Boox e-reader (the Leaf, the 7" screen is almost perfectly sized for manga). It's with Android, so I can use Mihon as well as Bookwalker, Kobo and Kindle (I strip the DRM from my e-books bought with the latter 2 stores though, so I can put it on my Komga server, so I haven't used their apps). Really convenient.