.htaccess and virtual host configuration for WP in its own directory

Eventually I solved it by moving my app/ folder and my wp/ folder into a subfolder, which becomes the web root.

Something like this:

my_project
 |
 \--vendor  <-- folder for composer packages
 |   |
 |   \...
 |
 \--wordpress  <-- Web Root
 |   |
 |   \--app  <-- custom wp-content folder
 |   |    |  
 |   |    \--mu-plugins
 |   |    \--plugins
 |   |    \--themes
 |   |
 |   \--core  <-- WordPress core code
 |
 |--all the other stuff like config, environment variables, SASS, Grunt, etc... outside the web root