First thing I would do is get shed of the Garrett. Second thing, get shed of the Whites. Then I would decide between the Nox and the Nokta Legend. In my case I would go with the Legend.
That is what I would do.
One more thing.. Just because the newer detectors have all the buttons and options doesn't necessarily mean you are required to learn them.. New detectors can be used as a turn on and go with factory presets just as easily with no adjustment required..