I believe Hyundai owns about 34% of Kia and Kia owns other companies owned by Hyundai. As a result, the companies are like cousins to each other. Many of the same components are shared, obviously, but some are not. I can't give you specific examples, however, the few times that I test drove a 2019 Santa Fe, the dash was very similar to my son's Sorento.
As far as not buying a Telluride because of the lack of availability, I say to each his own. Some people, like me, are willing to wait. I had to wait 5-6 weeks for my S-trim. Others took what was on the lot and were very happy. Yet, for those people who want an SX-Prestige, well......that's not going to happen from what I understand. It all depends on the trim and interior/exterior color you want I suppose.