Red Blue Cache line is Missing

DVR 19.1.4 on Mac - specs below.
I have no blue/red cache line. I have enabled optimized media, I have put the playback>render cache>smart and I don't get that line.
I have found an older thread with the same problem and followed its recommendations: delete render cache. Turn render cache off. Turn it back on.
I still do not get a render line.
I am going to apply special effects to a few frames and I definitely want them pre-rendered as my computer will not be able to play it in real time. I watched several YouTube videos to rendering/caching and could not find any more information on what else I could do.
I am not using an external hard drive - the project is on the main SSD of my 27"iMac.
What else could I try? Maybe rendering does not work at all on my system?
I have no blue/red cache line. I have enabled optimized media, I have put the playback>render cache>smart and I don't get that line.
I have found an older thread with the same problem and followed its recommendations: delete render cache. Turn render cache off. Turn it back on.
I still do not get a render line.
I am going to apply special effects to a few frames and I definitely want them pre-rendered as my computer will not be able to play it in real time. I watched several YouTube videos to rendering/caching and could not find any more information on what else I could do.
I am not using an external hard drive - the project is on the main SSD of my 27"iMac.
What else could I try? Maybe rendering does not work at all on my system?