I am not sure if you meant that you have a Cybex car seat..? In any case - if you don't need much terrain capability (which you don't mention, and from what I am reading, I see your priority is a low weight, a compact fold, and comfort for your baby), I would suggest the Cybex Mios which is reversible, lie-flat, compact and light, but also qa quality model that is comfortable for smaller babies, too. It also accepts a Cybex car seat.
The Cybex Eezy S-Twist+² could also make sense, very compact, reversible, light, and even if a bit simple, actually practical in most aspects. A Valco Ultra Trend could also be a nice light choice.
If you don't need a reversible model, try checking the Joie Litetrax Air which is actually affordable, folds reasonably flat, and can take some bumps at times. With adapters, a Cybex car seat or a Joie carrycot can be attached, too.
Now, check the options, think about your budget and what you liked or didn't here, and ask me again if you have more specific features in mind.