Been a while since I've seen an apache configuration. Curious about this part though:
ErrorLog /proc/1/fd/2
CustomLog /proc/1/fd/1 extended
What's that for? # ls -l /proc/1/fd/{1,2}
lrwx------ 1 root root 64 /proc/1/fd/1 -> /dev/null
lrwx------ 1 root root 64 /proc/1/fd/2 -> /dev/null
See: https://stackoverflow.com/a/40007799
Its sending logs to the container output instead of a file in the container.