Hi @Harry N Nomikos ,
If you grant edit permission level to the group in site level, the group will have edit permission to all lists and items. The group will also have access to lists with unique permission. To avoid this, we could create a group without site permission level. Then we could share the folder to the group with separate permission.
You can set the group permission with can edit or can view.
If the answer is helpful, please click "Accept Answer" and kindly upvote it. If you have extra questions about this answer, please click "Comment".
Note: Please follow the steps in our documentation to enable e-mail notifications if you want to receive the related email notification for this thread.