I’m not sure why…
But the nginx installer is creating server blocks and modifications that don’t… “work” with the rest of the config.
Please upload the whole nginx config form the output of:
nginx -T
[the reason/explanation/fix will be found somewhere in there]
In any event, we can always fallback to using --webroot as PLAN #B.
[we have 89 days to get this right - LOL]