You need high light and a CO2 injector to grow this stuff well. And once it has grown, it's difficult to keep the tank bottom clean. You can't rearrange the tank as easily etc.
I have 1.5 watts per gallon in my tank, it is considered low light. Some plants that do best in low light:
Anubias (any kind)
onion plant
java fern
java moss
amazon swords
cryptocorynes
I was able to grow all of these, I'm sure you could too.
The following may not be quite what you were thinking of, but might be worth considering, if you haven't already.
Dwarf 4 Leaf Clover is mid-to-low light.
It's obviously not 'grassy' but once it fills in it provides cover.
I wound up getting the regular 4 Leaf Clover instead of the Dwarf I'd ordered, which is not only larger but supposed to require a higher light level.
Nonetheless it seems to be doing OK and gradually spreading in my low-tech tanks, so I'd expect the Dwarf to do even better.
I believe Dwarf Sag is supposed to be fairly hardy and adaptable?