I now tried using my asus external UHD friendly drive and it actually came a bit further and created the files in .MakeMKV/ (see google drive link) but it still says failed to open dics at the end.
The fact that MakeMKV has now created a TGZ dump file means that the problem here is likely that MakeMKV just doesn't know your disk's decryption keys. In which case, you need to email your TGZ dump file to svq@makemkv.com. You can also try downloading the latest KEYDB.cfg file, copying it into MakeMKV's data directory (i.e. where MakeMKV also writes its TGZ dump files - /home/player/.MakeMKV in your case), and restarting MakeMKV, in case the public KEYDB database already has an entry for your disk.
Note that since you're using Linux, you must ensure that your KEYDB file is literally named "KEYDB.cfg" and not (say) "keydb.cfg", because Linux file systems are case-sensitive.
So I tried extracting the privtae data tar (that I downloaded from billycar11's guide) and put those files inside the MakeMKV directory and suddenly it worked for the external one. But I don't know about the internal one but I'll try that later. And I'll look forward to download the key files