Your Oppo should play 50GB DL bluray discs, and if so, I can point you in the right direction.
Register for the forums over at thestarwarstrilogy.com
Register in the FORUMS section, not just the main page.
At least for me, my forums login doesn’t access the main page.
In their download section there is information on how to download many different versions of our beloved trilogy.
There are 1080p ~40GB bluray ISOs in there for 4K77 and 4K83.
That’s where I got mine.
I even accessed usenet, but all I could get there were mkv files and like you I wanted the ISOs.
For the menus, language options, subtitles…
We’re not allowed to post links outside of their forum, so I can’t give the exact information required on here.
Check them out and see if this helps.
Good luck.
Thank you also! I do want it on a blu-ray just for ease of storage (and I have a rather large blu-ray collection of mostly 3D movies but others as well) so I will try this tomorrow with the hopes of getting the 1080p versions I can burn on a BD-R DL 50GB disc. Really love the 2160p DNR version though but I imagine it will look just as good on my 103" 2.35:1 screen since 1080p movies look super sharp on it.