[solved] /contao/install 404 not found on Ubuntu 20.04 local installation

Hello,
I'm trying to install a local dev environnement on my laptop under Ubuntu 20.04. I've installed lamp from Ubuntu official repos.from

1. I tried to transfer a Contao 4.4 prod website from a shared host.
As explained in the doc, I copied /files, /templates, composer.json and composer.lock to my local vhost and added /web/contao-manager.phar.php.
For the installation to work, I had to chmod -R 775.

At the end, when I click to Update the database, /myvhost/contao/install returns a 404 not found page.

2. I tried 3 times then I tried a fresh installation.
Same 404 error. When I look in the vhost directory, all 1st level directories (except /web) and files are locked with owner: www-data: create and suppress and group: www-data: files access. And the /app directory is missing.

Where is the problem ? In my Apache2 conf ?

Or in my vhost conf file ?

Code:

---

<VirtualHost *:80>
        #nom de domaine
    ServerName terea.test
        #on accepte aussi le www
    ServerAlias www.terea.test
        #logs d'erreur
    ErrorLog /var/log/apache2/error.terea.test.log
        #logs de connexion
    CustomLog /var/log/apache2/access.terea.test.log  common
        #Définition de la racine des sources php
    DocumentRoot "/var/vhosts/terea.test/web/"
    <directory "/var/vhosts/terea.test/web/">
        Options -Indexes +FollowSymLinks +MultiViews
        AllowOverride All
        Require all granted
    </Directory>
</VirtualHost>

---

Thanks for your help.