There is a "Stacey's engagement ring" for sale on the Ho11 website
[I’m just going to leave this here]
(https://www.amazon.com/Newmind-Template-Humanoid-Patterns-Measuring/dp/B09GL4L21W)
Color A’s last pic is very similar & would be easy to add just a few minor tweaks to it to make it their “own” design sketch.