I guess the fact that 80% of the installation is as good as it is makes me frustrated about the last 20%.

One example: the install expects that the data drive will be on a 1-2gb USB attached storage drive; the Odroid uses SATA, 6tb drives are very commonplace, and the process for formatting <4 | >4gb is apparently completely different in Linux?

To reiterate, the installer is really good, but someone stopped just short of making it great.

Regarding the UI, it's not terrible, but I hope that Nextcloud Corp invests some of their newly found riches on a top-class UX designer.