Add a user without them being able to view company books, only manage clients' books?

There's no need to go into all 50 clients and individually send invitations, @quickerbooker. I'll guide you on how to send an invite to a user so they can access all your clients in bulk.

Ensure to log in as admin using your QuickBooks Online Accountant (QBOA) account. 

Here's how you can add a new user to manage your client books:

1. Sign in to your QBOA account, then go to Team menu.
2. Click Add user.
3. Enter your team member's full name and email address.
4. In the Access section, select the dropdown ▼ choose Custom. 
5. In the YOUR FIRM BOOKS section, choose No access for Customers and accounts receivable and Vendors and creditors.
   
   
   
6. Check the boxes next to your client's name, then Hit Send invitation.
   
   

Moreover, check out this link to help you track and update your client list: Manage clients in QuickBooks Online Accountant.

Comment below if you have further questions about managing your accounting team in QBOA. I'll be here to help you. Take care!