Adobe Freezes/Crashes when Exporting 4k 60p

So, I already exported 4k 60p files which were about a similar size. It took quite long but worked with the settings you see in the export screenshot. My Radeon R200 Graphics card is quite old, so the project uses only software rendering. As I said, it worked before. But I'm also new to Pr. 

So I always had a red/yellow indicator in the sequence timeline and thought maybe this is too much for the CPU to do. So I pre-rendered (sequence -> in&out render) the individual clips in hopes it would make the exporting easier and faster. I made a new project, copied the sequence over, the same result. I made a new project and started new, adding, and cutting clips. Same result. 

It still crashes. See also the errors in the screenshot. Any ideas? It also crashes in different stages. I shortened the vid to be under 20 mins and under 8GB already. Changed VBR 2-pass to 1-pass. I have NO effects on any of the clips. the only thing you see with the first clip is an audio fade in. I just cut them. No stabilization, no transitions, nothing. 

What I'm trying next is a CBR of 53 which is the lower end of this video format. I'm following google's guide on the best settings, bitrate, and such.. takes approx. 3 hours. I'd report back in if that worked. 

Thanks in advance for your help and input. 

[edit] so I tried the CBR 53 but t also crashed. I then downgraded to 14.3.1 and it still crashed. Same with 14.3