Thanks! I did try reverting to MKL and test some more optimization runs - seems like the performance difference is minimal.
However, I did notice something interesting in Task Manager. The MATLAB Parallel pool is configured to run with 64 workers with 1 thread each, which corresponds to 64 processes showing up in Task Manager. Out of these, 32 of these show up as background processes with minimal CPU usage (0.1-0.2%), but proper RAM consumption (~1GB). The remaining 32 are grouped into 1 section and appear in the foreground Apps section. And out of these 32, only 1 has any significant CPU usage ( fluctuating between 10-40%).
I am not sure what exactly to make of this, but decided to put this out here anyway incase someone with more knowledge and experience than me can chime in.
I also performed a system profile with AMD uProf. It reports that the System Idle process [PID:0] occupied over 81% of the total CPU time during the profile, with the remaining MATLAB processes collectively occupying the remaining ~19%.