I just checked my own dbty necklaces and others from tpf. I think the rings in your chain are too big. Can't tell if the rings in the dbty are also big, because they are sideways. Please check out tpf photos for yourself.
The dbty chain is mainly open (very small) circular rings connected together. due to open circles, the chain gives the look of "floating in air". There are different size dbty chains for different size diamonds. "Thicker" chains have bigger and thicker circles. The chains for 15-pt and 20-pt diamonds are thicker than those for 5-pt to 10-pt. For your 20-pt dbty diamond, the thicker dbty chain in 14K or 18K gold is sturdy enough for daily wear.
Do you think the current chain is too thick for the diamond? Hmmmm. I was thinking if the current chain would look fine if there are smaller connector rings to the diamond. The diamond is 0.20 carat