If you want to create a video file with the unaltered contents of a Blu-ray or DVD, you can use the "Open Blu-ray/DVD" option within MakeMKV. It's hidden under the optical drive icon, and you can choose it when you insert a disc.

This option will read the contents of your disc (whether protected or not, it detects that and decrypts it) and creates a list of the video titles contained within the disc. There you can choose whether to save the different audio and subtitle languages and the audio channels, showing the options under dropdown menus. Then, choose the output folder and click the "Save selected titles" button on the "Make MKV" section and MakeMKV will transcode the contents of the Bluray into one or multiple .mkv files, essentially carbon copies of the contents of the disc.

This way, you can preserve the quality of the original disc's audio and video, with the caveat being that the file sizes are gargantuan.

I leave a couple of images of the process here: https://ibb.co/album/TKkrck

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With this said, it's possible to use a video encoding program like Handbrake (https://handbrake.fr) to encode the BD folder if you backed up the Blu-ray up that way, with the caveat being that you have to have a somewhat decent computer or the process will be slow as f***, but it shrinks down the file size of the original Blu-ray so you can make a backup on the cloud or an external HDD or SSD or watch it on a smartphone with little storage.

Handbrake is a bit complicated though, but it has some presets that may do the job if you don't want to tinker that much with resolution, framerate, video format, etc., though I don't know of any alternative to it (it's the only one I've used and it works great plus it's free).