Decking on sloping concrete with shallow end...

Decking help, I want to deck this area, the red line shows the level I want, the concrete is on a slope, the bit I'm struggling to work out is that on the left the height will only be the height of a brick, about 4", allowing for the decking board width, that doesn't leave much space underneath for a frame, or that the frame of 2x2 would be resting on the concrete rather than legs to hold the frame up. Any ideas?

Also, in the other picture, how do i deck up to the door over the PVC lip but still be under the door, can the board float over it? the doors meet the pvc lip at the bottom, ideally I dont want a gap there.
Thanks

You would want the deck boards under the pvc cill. I appreciate it may give you more space to play with but probably more of a headache overall.

Personally I would want the boards under the cill and feelnit would look neater