I’m not aware of any businesses in this field, though there may well be some. But what exactly is your objective? If it’s to run Nextcloud, TrueNAS is hardly necessary or even beneficial.
This is now the second thread you’ve started expressing the curious belief that Nextcloud is best run on top of TrueNAS. What makes you think this? And why didn’t you answer this question when we asked you on your other thread?