Apache2 custom error on ERR_BAD_SSL_CLIENT_AUTH_CERT

I have secured access to one of our server via User Certificate Authentication via following configuration:

<VirtualHost *:443>
    ServerAdmin [email protected]
    ServerName mydomain.de
    ServerAlias www.mydomain.de

    # SSL Configuration for the proxy
    SSlEngine on
    SSlCertificateFile /etc/ssl/certs/mdoamin.de-crt.pem
    SSLCertificateKeyFile /etc/ssl/private/mydomain.de-key.pem

    # Client Certificate Authentication Configuration
    SSLVerifyClient require
    SSLVerifyDepth 1
    SSLCACertificateFile /etc/apache2/ssl/authentication_ca.crt
    SSLOptions +StdEnvVars
    
    # Handle Errors
    ErrorDocument 403 /missing_cert.html

    # Reverse Proxy Configuration
        #ProxyRequests Off
    <Proxy *>
        Require all granted
    </Proxy>

    ProxyPass / http://localhost:9000/
    ProxyPassReverse / http://localhost:9000/

    ErrorLog ${APACHE_LOG_DIR}/error.log
    CustomLog ${APACHE_LOG_DIR}/access.log combined
</VirtualHost>

<VirtualHost *:80>
    ServerName mydomain.de
    ServerAlias mydomain.de
    Redirect permanent / https://mydomain.de/
</VirtualHost>

The configuration works well if the correct p12 cert is inserted into the browser. If I try to connect via a browser without the cert I get the ERR_BAD_SSL_CLIENT_AUTH_CERT as expected.

Instead, I want the unauthenticated user to allow accessing a missing_cert.html error document under /var/www/html.

I tried to provide a custom error via ErrorDocument but this seems either the wrong error code or the doesn't work at all.

I found a similar request (Tomcat redirect on ERR_BAD_SSL_CLIENT_AUTH_CERT) for a tomcat server, but I hope it would be more possible with a apache2.