Do you have that option activated from the preferences?
https://s3.amazonaws.com/zotero.org/images/forums/u265723/aszkdalmmv8nw71yku3m.png
https://www.zotero.org/support/preferences/general#groups

Hello again. I needed to update some tags in my personal library. After deleting the folder with the old tags from the group library and adding the folder with the new tags from my personal library to the group library, it keeps displaying the old tags. How can I change that?

I activated the tags option in the settings.
I also emptied the trash in the group library before dragging them from my personal library.

@GamzeGulGuner

After deleting the folder with the old tags from the group library and adding the folder with the new tags from my personal library to the group library

The tags are associated with the items. Deleting a collection will not remove the items from the group library.
If you add a collection to the group library, with the old items still in there, it will use the items that are still in your group library instead of the ones you have modified in your personal library.

To update the items in the group library, you need to delete them with the collection first, so that the updated items can be added again.

You can do that from a right-click on the collection -> "Delete Collection and Items":
https://s3.amazonaws.com/zotero.org/images/forums/u265723/snv7dletf5c173nsvgwe.png

Do you also know how I can remove all of these notes at once? Thanks in advance.

https://s3.amazonaws.com/zotero.org/images/forums/u14088282/ihzphasoopdje77qj025.jpg