First you need sloped recessed can fixtures so the beam shines down (unlless you want the light to highlight something on the wall)

2.5 - 3' from the walls and 3 ft. apart. Why 6" cans? and why just 4?

Is that the only light source in the room? How tall is the ceiling?

How about a photo of the whole room at eye level?

I don't know how you arrived at (4) fixtures. They should be placed based on the room(s) layout and furniture. Just from the small frame of the picture, you might have a very complicated layout, with multiple doors within the seating area and a very prominent plant shelf.

Ugh no ceiling lights. Table and floor lamps, sconces, up lights.

NO 6" ever again they are dated beyond anything. You will find on a sloped ceiling pots lights are kind of usesles. Lighting is best when layered so how a bout a nice chandelier where the fan was and then add table lamps and floor lamps instead of pot lights.

Replace fan with multi bulb chandelier, on dimmer. Improve the bedside lamps.

Ever considered painting the sloped ceiling the same as the walls?

Loving your guys' ideas! I'm now decided against the recessed can lights, lol.

What's your price point? How tall are the ceilings? What are the room measurements? 12x12, 20x20? It helps on deciding the right size for the fixture.

Ooh love that chandelier on cape posted

It would be a good idea to show us the whole room.

Another vote for throwing light upward. The area behind the crown molding looks to be a great place to put lights that are aimed at the ceiling. Set them back and the fixtures disappear, leaving only the lighting effect.

You might also consider replacing the dark ceiling fan with a white one, no lights. Since the bedroom is basically in an attic, the fan might come in handy.

Based on your reference for modern minimalist, thought this might help.

With the height of your ceiling + the look you are after, the light will be more decorative so it‘s important to also narrow down practical lighting needs.

You mentioned you will be painting the room white, but that’s not enough to help. If you can hold off choosing and provide a picture of finished room, you’ll get more relevant examples both size and style wise.

For a modern minimalist bedroom, I’d definitely consider something more decorative than recessed lighting, especially with white walls. A sculptural wall or pendant light can give you the lighting you need while also becoming part of the room design. I recently put together a video comparing 8 different moon-inspired lighting ideas — wall lights, pendants and some more unusual options. It might give you a few ideas for the direction you want to take:
https://youtu.be/g-R98L8EdII