I did it a little while ago. Was very easy. Download books with kindle app, load them into Calibre and use a one click plugin to strip the DRM. I think this was the step-by-step I used.

https://nerdschalk.com/remove-drm-kindle-books-de-drm/

The guide the other user commented looks pretty good, better than the one i followed. lol
If you run into issues let us know.

At least I’m hoping that there’ll still be a spectrum of both BW and color screens available. Apparently many seem to like/prefer colour screen, and the screen door effect and worse contrast doesn’t seem to bother a lot of people. Some even prefer the more textured look of the screen door effect, though I don’t know myself as I’ve never tried a colour screen. Either way, I’d be hesitant to try one, and as I kept my Kobo Aura One for like 7 years it’ll be quite some time before I upgrade my current Kobo Libra 2. If I have some spare cash I might be inclined to try a colour e-reader as an alternative to my current one, but it’s not high on my priority list.

But yeah, it definitely seems that Kobo is pushing their colour screens as they’re only selling the Libra in colour now. Might be that they release a B/W once the hype dies out a bit though.

I’m farsighted and have an astigmatism, so I have to read with glasses, and maybe that’s the issue, but I just held my Clara really close to my face and I don’t notice any screen door effect.