Found the original discussion: 🚀 Exciting Improvements Coming to Moodle. I saw it earlier, but then set aside "for future" and forgot. I usually stay with the LTS, having upgraded to 4.5 LTS only this summer. Thought of making an exception this time, moving to 5.1 next summer, mainly because of the new question sharing behaviour since 5.0.
No, I am not qualified to comment on whether the /public will enhance security, nor streamline deployment and modernize the codebase.
To my original question, I believe, I can get 5.1 going with the help of MDL-83424 on a new FQDN. My test sites are on my own domain. So, I can get unlimited sub-domains - and avoid the mydomain/subdir/ kind of URLs. The production domains are different. They belong to institutions and I won't get sub-domains. But I have plenty of time till then to understand the new Apache rules. (Or earlier, when we'll have exciting times in the Installing and upgrading help forum, starting 6 October.
)
I'd be glad if there's better documentation than that zip file. The content look like they are for Windows or Mac, not Linux, ideally Debian. And what about Nginx?