Hello decoamorim,
You can select all of the slots, then click on the dot under the eye column to deactivate them all at once.
Please note that this will only have an effect in the editor and not at runtime or in the preview view, you'll also notice that you can't key slots, this is because you should activate and deactivate attachments and not slots. esotericsoftware.com/spine-basic-concepts Key Frames - Spine User Guide: Attachments

I recommend grouping attachments by piece (such as all the left eyes) under the same slot (e.g. the left eye slot) so that it will be easier to activate and deactivate them.

When you filter the tree on attachments, they should be sorted alphabetically, therefore making it easy to select all of the attachments for a certain view and switch to it. I still recommend creating a dummy animation to store a turnaround of your character to make it easy to copy and paste a certain pose. Tree - Spine User Guide: Filters

You can see an example of this process in this series of videos: Twitch: Rigging an 8-direction character for animation in Spine Pt.3 - YouTube

Additionally, selection groups might be useful (if somewhat limited, since you need to remember the groups):
Tools - Spine User Guide: Selection groups