I really appreciate your help, but PHP is still not working
This is how my phpmyadmin configuration file looks like after all your edits:
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server{
listen 80;
server_name phpmyadmin;
access_log /var/log/phpmyadmin.access_log;
error_log /var/log/phpmyadmin.error_log;

location / {
return 404;
}

location /phpmyadmin {
root /usr/share;
index index.php;
}

location ~ ^/phpmyadmin/.+\.php$ {
fastcgi_pass 127.0.0.1:9000;
fastcgi_param SCRIPT_FILENAME /usr/share$fastcgi_script_name;
include fastcgi_params;
}
}
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