How to avoid "skipping copy phase strip" warning (because "binary is code signed”) without setting "strip debug symbols during copy" to NO?
You can't. Xcode doesn't detect that the code signed framework is already stripped. The warning is harmless.
The size of your shipped binary will not be influenced by this setting. That is another setting, named "Strip Linked Product". You can leave that set to YES. See also: https://stackoverflow.com/a/7915911/923288
One way to do this is to go into the General tab of your app, scroll down to "Frameworks, Libraries and Embedded Content", find the offending library that should be in that list and change "Embed & Sign" into "Do Not Embed", this will certainly get rid of the warning and the app would work on the simulator fine, however, depending on how the lib was coded it's not 100% guaranteed that it would work on the device (being debugged through Xcode), apart from that it should work fine.
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