If you've ever juggled two SIM cards on a Samsung Galaxy phone, you know the drill: swapping between lines for data, calls, or texts isn't exactly seamless. You're constantly diving into settings, tapping through menus, and second-guessing which SIM is actually active. For frequent travelers, dual-line professionals, or anyone managing multiple carriers, it's a friction point that adds up fast. But Samsung's upcoming One UI 8.5 update is about to change that—and if you're a power user who...