Understanding that you aren’t looking to graft but just wanted to note that England’s Orchard and Nursery might have Raintree Select as a scion option. I also see they have other rare varieties like Hidden Springs, Wang Bo, Sherwood, Monez, and Chorus. There isn’t much information on these rare varieties but from what I saw online Monez is reported to taste good and Wang Bo is a large fruit variety. lmvian on this forum is growing out seeds of Wang Bo and working to root cuttings so we may learn more about that one if lmvian is successful and shares the results (The other Goumi - #25 by lmvian)
Also just noting that cheap grafting tools on amazon look to be on sale for Black Friday (ex Amazon.com : FUNTECK 2-in-1 Grafting Tools Pruner Kit, V-Graft Omega-Graft and U-Graft, Perfect for Fruit Tree Grafting, Including Grafting Tapes, Grafting Knife & Replacement Blades : Patio, Lawn & Garden). I’m going to try grafting for the first time this spring using one that I ordered so I’ll see how they are. These might be awful, but I figured for $20 it would be worth experimenting. I realize you have circumstances that make grafting an unattractive option but wonder if one of these tools along with a small folding table or stool to brace against might allow you to give it a try.