When you want to move documents in bulk from one Slite workspace to another, you can export and re-import your content. But before doing this, have a look at this workaround which could save you some time.
.1Make your channel public (you'll make it private again or delete it once the migration is done).
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.2Select the option to show the "duplication" button
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.3Open the channel's public link and click on "duplicate". You'll then have to choose the new Slite workspace you want to use as the destination.
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.4Don't forget to turn the initial channel that you made public back to private or delete it