Unable to export lengthy live performance from Media Encoder

I recently shot a live event for a client that is extremely lengthy. My deliverable is a roughly 1.5-hour long cut that I am trying to get exported for my client. I assumed that it would be best to export this via Media Encoder rather than Premiere, but the export time is 25 hours and no matter what I do I am unable to get through these 25 hours without either my computer or Media Encoder crashing.

My Export settings are as follows:

HEVC (H.265)

4K

23.976 fps

Use Maximum Render Quality

My iMac specs are:

3.4 ghz Quad-Core i5

16 gb 2400 mhz DDR4 

I have disabled the sleep on my computer to avoid any interruptions. I have tried closing all applications except for Media Encoder. I have gone into Media Encoder preferences and allocated as much ram as possible to the software. No matter what I do I cannot get this export completed. I have been trying all week.

The only error I have seen is that my computer has run out of application memory. I have no experience exporting feature-length projects, so I am hoping that there is some workaround for me to be able to get an uncut version to my client. Otherwise, the only fix I can think of is to export the show in segments.

Can anyone advise?