How can I restrict Account owners and Account team members from viewing Opportunities?

You need to define a custom role so that members of the Account Team or Account Territory can't view opportunities associated with the account unless they're also members of the opportunity team.

For example, the predefined Sales Representative role has the following duties added:

• Opportunity Sales Representative Duty

• Opportunity Territory Resource Duty

• Opportunity Sales Account Sales Representative Duty

• Opportunity Sales Account Territory Resource Duty

Define a custom role similar to Sales Representative but without the Opportunity Sales Account Sales Representative Duty and Opportunity Sales Account Territory Resource Duty duties. To restrict opportunity visibility based on the Opportunity Owner, Team or Territory, assign users a custom role that has only the following duties:

• Opportunity Sales Representative Duty

• Opportunity Territory Resource Duty

See the related topics in the Securing Sales and Fusion Service guide for more information on modifying the default roles.