Don't look at it like that partner, I found this thread to be hilarious because I feel the complete opposite. I've played unlocked camera for 5 years and have NEVER been able to use the locked camera mode, I don't even use the space-bar which locks the camera whilst in unlocked mode.
I would honestly say if you got to Plat with what you're doing, stick to it man. To some extent, the locked camera may have it's advantages as well, 1 being that you never lose sight of your champ which can help you in team fights. I have this issue every once in a blue moon when during a team fight, everyone splits and goes in all directions and I miss a follow up attack or an escape because I wasn't panning (I guess that's what you call it) properly while in the unlocked camera mode.
But anyway, to answer your question, you just need to leave the unlocked camera in a position that gives you the greatest field of view, and leave it there. So if I'm up top for example, the rest of the map and what's going on is completely irrelevant, so I leave the camera like diagonal to the river so that I can see both me and my opponent, as well as the bush and river. If my wave pushes towards my opponents tower, then I pan it once so that the waves are in the middle and both me and my opponent are visible as well as the river in the bottom. I don't know if any of that makes any sense at all playa, but I guess what I'm getting at is if you think you need to move the camera around in unlocked mode constantly, then you're definitely doing it wrong haha.
But to each their own, that's what makes the world go round.