per-vhost metrics is the big one for us. We're not going to pay $2,500 just to get them though.

If you enable the stub status, that gives you metrics for the master process and not any of the virtual hosts.

I wrote something out of our need for better monitoring/metrics for Nginx here: https://luameter.com/ And quite a few people are using it for per-vhost metrics use case just like you said. Also if you prefer something simpler and open source I also wrote this https://github.com/lebinh/ngxtop

Second project is a hack that's reading log scripts.

That's not comparable to a proper monitoring page and exposing its stats by statsd (or similar) for integration with a real monitoring system.

nginx free edition is a black box, hence the criticism.

I've had basic nginx vhost stats in my Centmin Mod LEMP stack installer for ages - not as detailed but works https://centminmod.com/nginx.html#vhoststats. Using nginx module https://github.com/vozlt/nginx-module-vts

and TLS v1.3 works fine for me too https://community.centminmod.com/posts/48818/