Your code has several expressions of the form
x*log2(1+y/x)
which can be reformulated as
-rel_entr(x,x+y)/log(2)
The extra stuff in the denominator can be absorbed into the y.
I recommend use of CVX 2.2 with Mosek 9.x if available to you; otherwise follow the instructions at CVXQUAD: How to use CVXQUAD's Pade Approximant instead of CVX's unreliable Successive Approximation for GP mode, log, exp, entr, rel_entr, kl_div, log_det, det_rootn, exponential cone. CVXQUAD's Quantum (Matrix) Entropy & Matrix Log related functions .
Note: This is the most common reformulation in this forum. This is the 2nd one today.