For task lighting 70-80 footcandles or 450 lumens at the counter. DMF is one source. Products - DMF Lighting More than one 4" recessed to avoid shadowing.

Lumens: 750 lm (9.5W), 1000 lm (12.5W), 1250 lm (14.3W), 1500 (14.3W) at the fixture. More in commercial M line Link

Color Quality: 93 CRI, 2-step SDCM

Color Temperature: 2700K, 3000K, 3500K, 4000K, Warm Dim (3000K – 1800K)

Beam Spread: 15° Narrow Spot, 25° Spot, 40° Flood, 60° Wide Flood, 90° General, Linear Spread, Soft Focus

Dimming: TRIAC/ELV (1%, 120 V only)

We used recessed lights from ELCO. You need better option than the basic stuff found at the big box stores.

https://www.elcolighting.com/product-systems

Not enough information.

Flicker free and dimmable pertains to choosing a dimmable fixture/'bulb' and compatible switch.

You have not specified if you want a pendant, ceiling mount flush/semi-flush, or recessed fixture.

The number of fixtures and placement will depend on type, style, and performance spec of the fixture, and layout of kitchen including size of island.

For a recessed light within a sloped ceiling, the fixture should be a gimbal so the throw can be perpendicular to the intended surface. Gimbal styles range from just the trim being rotatable to the inner housing itself being rotatable. The ceiling structure might determine what style you choose. As well as being 8' above the island and the value and design aesthetic of the kitchen and overall house.