I have recently embarked on my own fan edit odyssey, ripping and demuxing 20 blu-ray discs for the project I am working on.

After much trial & error I settled on using MP4tools on my Mac to demux the .mkv files ripped from the blu-ray discs using MakeMKV (admittedly on a PC).

MP4tools ‘rewraps’ the .mkv files (in my case I chose .mp4 and 5.1 channel AAC files) allowing you to edit natively in Premiere Pro etc. The ‘rewrapping’ process is much quicker than converting the .mkv into another format, and because it isn’t actually converting the file, there is no quality loss.

I wholeheartedly recommend MP4tools - sure you could download a bunch of command line tools and do the same thing, but I found the MP4tools workflow to be very straightforward.

I hope this helps!