Permission to view uploaded files

Hi all,
Although I have submitted a ticket, I still wanna seek the help from the expertssssss in this community...
Currently our company account has 2 types of users. The tier-1 is "brand admin" and responsible for all survey filedwork and resticted data handling. The tier-2 is only responsible for handling tickets and DO NOT has any authorities in editing surveys.
Now we have a form for customers to submit thier personal inormation and upload supporting documents (e.g. address proof). Tickets will be auto generated form tier-2 users to handle. Although the link for this supporting doc can be displayed in the tickets, they cannot view it as they do not have the permission.
I tried changing the collaboration and user types, but they all failed.
Is there any setting we can do in user types or collaboration so that tier-2 users can maintain their limited permission but view those uploaded files?
That make us headache😖...thanks!!!!
P.S. We do not prefer the link can be accessed by "anyone" publicly.