If you can, look into local jewelers who can craft you something handmade with ethically sourced stones. I’m in Seattle and we have Valerie Madison who does great engagement sets and Everling Jewelry who uses recycled metals. A local artist will be able to recommend something within your budget, and your SO can and should be involved, as another poster mentioned.
I went the same route, it was significantly less expensive to get a nicer custom ring made by a local jewler I knew, to my spec/design then to get a commodity one from a store.