The short answer is no—you don’t need to fly for a Delta Connection carrier to eventually get hired by Delta. Plenty of Delta pilots have come from SkyWest, Republic, Envoy, PSA, Mesa, Horizon, Endeavor, and many other regional and Part 135 operators. Since you want to live in Atlanta, I’d put more emphasis on finding a regional that offers a base and quality of life that works well for you rather than chasing one specific airline solely because it’s affiliated with Delta. That said, hiring trends change over time, so it’s smart to stay flexible. Your goal should be to become the strongest pilot you can be, regardless of which regional gets you there. Hope that helps!