Can you explain, what you mean with:
To my knowledge, there are some aspects of NC, which are Enterprise like when it comes to real business deployment with official support for things like clustering, outlook integration, etc. But otherwise, NC has not a real and software wise separation between community and enterprise version. Please point me to your information source!
For me Nextcloud is pretty solid on the “production” channel.
Can you elaborate on this one a little further? What were your problems? What does the logs say? These error messages on your client; were they the same for your own server and hosted ones? It seemed you have used OC/NC for a long time? Maybe it is time to start a fresh instance (with a complete reset of clients and their config and with only the most important parts migrated on the server?
I think you mean the case when hosting it yourself on a root server, do you?
I for myself have a root server 200 of kilometres away, with a couple of services; among others NC, which serves a hand full of users with Linux and Android clients without considerable problems! Of course you have to precisely setup the server itself, the software and every needed parts. It does afford quite a lot of knowledge, but all in all when it comes to NC itself, it is one of the easy ones to setup and maintain out there.
So from my side as an answer to you question
It has always meant to be used by end-users and still is. It has its problems and as for me, sometimes NC releases features and versions a little bit to early and immature, but you always can switch to “Production” channel server side, let features mature and have a pretty stable life.
And yes, I mean this in every aspect, because:
If you mean an “end-user” who is only capable of installing the client on its desktop or device and use NC like “Dropbox, OneDrive, Box etc.”, there are providers for this. But maybe some hosters don’t do a good job. I see this as a potential problem as a whole concerning the brand Nextcloud. But like @SolarDesalination mentioned, all in all, it seems there are some good ones available. So yes, NC is meant to be used.
If you mean an “end-user” who is capable of providing himself/herself the complete package (= server, too). Then it is of course a comprehensive task, because it is always a comprehensive task providing your own server or service. But I can tell you, that Nextcloud is (because of its architecture and technical details) one of the easiest to setup and manage and at least my setup does not “constantly need on-the-fly back-end tinkering” and I think for quite a lot user it is the same. But sometimes you have to do a little work on the server, e.g. after an upgrade. But this is always the thing of self hosting. Nowhere in self hosting it is just like throwing a binary on one machine (= desktop), then a binary on another machine (= server), then letting some magic happen and done forever! It is not gonna happen! Never! Even not with Cloudron! There will always occur problems with every software. The only question is: Want full control and host yourself? Do it yourself! And NC lets you do this in a acceptable way! So yes, NC is meant to be used by the “other” end-user as well.
For me as an “end-user” Nextcloud is working pretty well, not perfect though!
EDIT: some typo