Adherance and Durability of self-levelling compound for kitchen floor

Yes.

You can certainly do the latter...

If you go for one of the better "latex" versions, then I expect that painted would work quite well unless you are feathering very thinly (i.e. less than a few mm) at the edges.

yes.

its durable enough in reasonable thicknesses.

But I'd tile it.

In fact when I did my kitchen, I used variable thickness rapid set tile cement instead of SLC ... string lines across the kitchen to get the levelled finished floor, and laid to the lines using a LOT of cement.

And when it got really deep - like 3 " - I used bits of broken tiles and cement that was going off to bulk out the gap.

Based on my experience with FBall Stopgap 300:

Yes.

When I had friable substrates I soaked then in 1:1 diluted SBR first.

And always use the green P75 (IIRC) primer they tell you to - that forms an efficient bond layer for the Stopgap 300.

As to "how durable" - it is described as "not a wear layer". For occasional use, it's quite tough - but washing machines etc are going to gouge it eventually. So no, you need a surface.