Would a quilt work for a ground-sleeper?

I am interested in a "quilt" 15-20 degree rated UL sleep system.

I have read the GoLite Ultra 20-degree UL is not generously temperature rated, meaning cold.

I am 5'6" female, not a cold-sleeper.

I sleep on my back, on my side, and on my stomach.

The only "mummy" bag I like is a MontBell Super Stretch.

I have always been of the opinion the "down" under me is pretty much wasted. I am an "early-adopter" and so my first and second Marmot down "quilt" was too cold.

Does anyone have experience and success using a quilt for sleeping on the ground? What pad(s)?

Down or synthetic?
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