The general rule is always to model it as you would build it.
That angle bit isn't a roof. It's a parapet wall with a decorative roof-like face that would probably be over-built on site, or pre-fabricated.
The flat roof, if indeed flat, could be done with the slab tool or the roof tool - but since you show a skylight, the roof tool would be the ideal choice. In reality, the roof will not (or had better not) be flat - but will be angled towards drainage scuppers or channels.
The vertical parapet wall on the interior-roof side would be flashed/covered with a membrane that is part of the roof system. It could be modeled as a wall (as it would be built) - with the angle bit as a roof, etc, depending on your desired sectional detail. Or, just the assemblage could be modeled, as you've done, with a complex profile or a Morph.
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