Yes, the Tag is an object itself… that’s not what I meant (that’s a given).
You also need an object-tag datatype - in your case a content-tag datatype (don’t use a list field on the content datatype).
Then just do a search for content-tags, whose tag is in the defined list of tags, grouped by content, each item’s content.
That will give you all the ‘content’ items who have at least one tag in the defined list of tags, and is all done directly on the database query itself.