If you are using multiple SNR points, then use parfor statement which is commented out in the code to have faster simulations.
This parfor statement code is in the Processing Loop section.
The other aspects include disabling HARQ process, if that is not the point of interest. You can even reduce the number of HARQ processes.
In general, the channel model does multi-path fading generation for each slot and the characteristics of channel will lead to long simulations.
Also, just to note, numerology also play a role. For 1000 frames and if used SCS 120 kHz, then the simulation is run over 80,000 slots. So, going for higher SCS, takes much more time than 15 kHz.
Hope this helps.