Thanks everybody for the input, I will definitely be trying out some things here.
We have just 2 channels of audio. All 3 camera files have the same audio (for 6 tracks) but the extras are deleted and we just use 2.
It sounds as if there simply isn’t much to do except wait for processes to finish either before of after the editing, or turn into proxies.
Would it help to initially cut the file into 2 or 3 pieces each?
I will also look into getting RAID drives as well as it seems one lone SSD and laptop may just be too slow.