This should be a new release. And a single 76 track release. As there are no CDs then it can be all in one long list as this is Digital Media.
I expect that other one is actually ripped from CDs - hence the six disks.
Interesting to note how the other volumes are done.
https://musicbrainz.org/search?query=The%20Sound%20of%20SceneSat&type=release&method=indexed
There is a mix of both - some are split up, others are left as a long list.
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The short cut that I would do is a slightly naughty cheat, but not sure any other way around it.
I would do as you did - manually using the track parser copy all the tracks across in batches.
I have done multi-disk releases like this and then sat there and worked through that RECORDINGS page manually selecting each recording one by one… and that is a right boring pain, but it is at least correct.
The “cheat” step would be to be instead create NEW recordings for all of them. Just let the Recordings Page make a new set. Get to the end and hit Save.
Then return to this same page and use the Mass Merge Recordings script to merge the two sets of releases together. (Just make sure you triple check that you are merging in the correct direction.)
After seven days your temporary set of 78 fresh recordings without credits will merge into the current set of recordings and pick up any relevant credits, etc.