On most rims the strength of the rim is far less than the forces generated by the spokes, so the condition of the unspoked rim can be compensated in the build. It's the spoking that determines the final roundness.
Obviously that needs to be qualified. Rims come in a variety of weights and shapes, and for example a deep rim will be far less amenable to the spoke forces a in radial direction than a shallow one. Likewise wider rims resist the spokes more in terms of wobble. Also, long gentle distortions are less of a problem than local ones.
Back in the dark ages of light squirrely rims, most had distortion at the joint and you'd get a quick low, high,low zone (or the other way around) We considered a wheel aligned when the whole wheel was better than the joint zone.
On your wheel you have no way of knowing if hop is in the rim itself or, as I suspect, is imposed on it by the spokes. Easing the tension will help give you an idea, plus give the rim some freedom to flow. There's no need, and little to gain by taking it apart entirely.
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FB
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