since I have now capabilities to view 4k, I was really curious to get a UHD in my collection. So maybe my issue is absolutely newbish, my deepest apologies in advance

From the prompts I would get that there is no key yet, but the disc is quite old already.
My drive is a Pioneer BD-RW BDR-XD06U, my system is arch with build from AUR which is currently MKV 1.15.3.
Attached is the log file and the mpls and clpi files.
Hopefully I didn't oversee anything.