Simple disciplined convex programming error

The first thing you must do is learn something about convex optimization.

Carefully read Why isn't CVX accepting my model? READ THIS FIRST!

Then perhaps the first 5 or so chapters of https://web.stanford.edu/~boyd/cvxbook/

It is possible CXVQUAD (add-on to CVX) has some additional matrix level functions which might be of interest to you. https://github.com/hfawzi/cvxquad But that is not likely to work out well unless you really understand what these functions mean mathematically.