My free solution was: I rip 3D blu ray using MakeMKV (there is a time within which is free, but that time can be extended infinitely; of course if you find it very useful it would be fair to purchase it); this will create a backup file that is without protections and identical to the original (so huge). Then I use BD3D2MK3D that will process such a file to create SBS compressed that can is read on lumepad. I usually do not put the files on lumepad, but I stream them from a pc using Jellyfin and the app developed by @jakedowns.