Cubase 13 / MacOS: Only partial audio track playback

I have seen a post here from almost 10 years ago, describing a very familiar issue:

I am not sure if this is the same glitch, however.

What’s noticeable though is that since Cubase V12 I have increasingly experienced issues with the playback of more than 5 or more audio tracks simultaneously.

The audio files are loaded from a SMB share on my NAS - could that have anything to do with that?

I have increased the audio buffer to 768 - but it changes nothing.

My question is: shouldn’t Cubase be optimized enough for this kind of scenario?

And has anyone experienced similar issues?

Here is a quick screencap of how my project looks like:

Currently, there are 16 track playing simultaneously at some timeframes but I am going to add more sounds later on. I constantly have to go back and restart the playback until I hear everything properly. This gets annoying really fast.

My system is a Mac Studio Ultra with 128GB of RAM - running on Ventura.