Exclusivism is not really about truth claims, but about practice, about living. If you are living a Catholic life, then you are not leading a Protestant life; and vice versa - and there are many subdivisions within this.
Each denomination has a different ideal of how to live, and that ideal is exclusive - at most you could switch from one to the other, or back and forth; but that would limit the degree of attainment within any one of them.
Each way of life has pros and cons, and would be more or less suitable for different individuals (who have different faults and abilities); each is incomplete and distorted - but each could be organized around the same simple principle. What is it?
As WmJas said: "Faith does not mean “accurate knowledge.” It means trust. That’s why Christ said little children are capable of it..."
Trust in Christ as Lord and Saviour.
Different ways of life, built around that simple principle.