I’ve been looking at the entire community questions related to my subject but still after all those years, Shopify didn’t manage to exclude a tag from a collection.
It should be one of the basic structures on Shopify…
Hey there, you can try using our app Advanced Collections - https://apps.shopify.com/advanced-custom-collections - to create collections which exclude product tags. What is created is just a normal manual Shopify collection which the app sync periodically according to the conditions chosen, and you can use it in the Shopify admin for various purposes e.g. for discount codes. There is a 7-day free trial to try it out. Hope this helps!