I've just come across this huge roadblock, just before we were hoping to go live with a public survey. Unfortunately it's now put us back to square one and searching for an alternative solution away from Survey123.
In our context, we are working in the remote backcountry of New Zealand, and so have to be working offline. I have created a vector tile package to be downloaded with the survey form, which all works offline, and seemed to be good to go. Everything is shared publicly.
However, I have just found the issue whereby people without an AGOL account cannot access the offline maps. Following your workflow of sharing the URL works for them to download the survey itself (though that is quite a cumbersome workflow), but then it is not possible to download offline maps without an account.
I'm also of the opinion that it's conflicting to have online documentation talking about sharing surveys publicly and how anyone can then access them and use them, yet there is a fundamental restriction on this being able to be done easily, and done at all offline.
It would be great to have Survey123 configured so that 'shared publicly' really means that the public can use the full capability of the app.
