Override single setting in default Apache <VirtualHost> block - apache

Question

In debian's default apache2 configuration, /etc/apache2/sites-enabled/000-default contains a lot of settings for the default VirtualHost:
<VirtualHost *:80>
# Many good settings here, among them:
CustomLog ${APACHE_LOG_DIR}/access.log combined
ScriptAlias /cgi-bin/ /usr/lib/cgi-bin/
</VirtualHost>
In another configuration file, I'd like to override a single one of them, the CustomLog setting, so that logs go somewhere else. I don't want to copy or mess with all the other settings, e.g. ScriptAlias. But I still want it to apply to <VirtualHost *:80>.
Is that possible?
What I tried
I tried putting this in
/etc/apache2/sites-enabled/001-mylog:
<VirtualHost *:80>
CustomLog ${APACHE_LOG_DIR}/my.log combined
</VirtualHost>
That has no effect, presumably because apache only looks at the first <VirtualHost> section, and /etc/apache2/sites-enabled/000-default gets loaded before /etc/apache2/sites-enabled/001-mylog.
Instead I tried putting the same snippet in /etc/apache2/conf.d/mylog, that gets loaded before /etc/apache2/sites-enabled/000-default because /etc/apache2/apache2.conf has an Include conf.d/ before Include sites-enabled/. That does override the CustomLog value as I wanted. But now the ScriptAlias from /etc/apache2/sites-enabled/000-default doesn't take effect.
I'd like to avoid duplicating everything from /etc/apache2/sites-enabled/000-default effectively creating a fork of the default debian apache configuration file.
Documentation
Apache HTTP Server - core documentation has this rather vague:
When a request is received, the server first maps it to the best matching
based on the local IP address and port combination only.
Non-wildcards have a higher precedence. If no match based on IP and port occurs
at all, the "main" server configuration is used.
If multiple virtual hosts contain the best matching IP address and port, the
server selects from these virtual hosts the best match based on the requested
hostname. If no matching name-based virtual host is found, then the first
listed virtual host that matched the IP address will be used. As a consequence,
the first listed virtual host for a given IP address and port combination is
default virtual host for that IP and port combination.
<VirtualHost> doesn't behave like <Directory>
Very confusingly, it looks to me as if for <VirtualHost> directives, only a single matching instance is considered. But for e.g. <Directory> directives, they are added/combined, so that:
<Directory "/some/dir">
Options Indexes MultiViews FollowSymLinks
</Directory>
<Directory "/some/dir">
AllowOverride None
Order deny,allow
Allow from all
</Directory>
is equivalent to:
<Directory "/some/dir">
Options Indexes MultiViews FollowSymLinks
AllowOverride None
Order deny,allow
Allow from all
</Directory>
But that this mechanism doesn't work for <VirtualHost> :-(
Edit: This is not the same as Sharing configuration between several VHosts, because debian's default VirtualHost doesn't use any of those solutions. But perhaps others can find inspiration in that answer.

Answer 1

I get the same puzzle for the multiple vhosts'(virtual hosts') definition. Do they override(redefine), overlap? Or there are other veiled details inside?
I find some links for this puzzle as following:
https://www.thegeekstuff.com/2011/07/apache-virtual-host/
https://httpd.apache.org/docs/2.4/vhosts/examples.html
With cautions to these examples inside, I could say the vhosts' definitions are not the same (even they look like the same). The difference mainly lays on the SeverName inside definition. Apache httpd server distinguishes the different vhost definitions based on ServerName inside(each vhost definition), not the IP Address or Port Number as listed in the <VirtualHost> header.
This puzzle keeps coming and going since there lacks explicit explanation for this topic(in the web). I hope this post can help to relieve this mindboggler in a way.