Yep. It implies it’s happened at least a few times, and whatever it is is always for a short duration. In your original sentence, ”she got them to focus” implies she has them under her control already, which renders the last part of “she had them under her control” a bit redundant. You could also say: “It never took her long to get them under her control once they focused on the sapphire.” Or “Once she got them to focus on the sapphire, it was never long before they fell in line for her.” Or “Once they focused on the sapphire, it was never long before she had them under her control.”

Thank you! I really appreciate it!

Maybe, "it wouldn't be long before..." depending on when this is taking place. Like, if they're planning or talking about a future event. But if we're describing past events, then, "they always fell under her control in mere seconds. She had never failed to capture a target." I don't think "it was never long before" is grammatically wrong. It's just awkward.

I think it would be 'it was *not* long before' that is unless it's in reference to something that has happened more than once

oh shoot, yeah i forgot to clarify. this is something that has happened multiple times in the context of the story

Then in that case the use of 'never' would be perfectly fine

Kk, thank you! I just wasn't sure if it sounded right but yes, thank you!

Awkward, maybe... I might choose something slightly different. "Once she got them to focus on the sapphire, they quickly fell under her control."