Helper functions outside application and system folders

Hello, I have a set of helpers that used by a number of applications in CI3. They are in the vendor folder and loaded with composer. I added to composer.json:

Code:

"autoload": {
       "files": [
        "vendor/diego/helpers/campos_helper.php",
        "vendor/diego/helpers/tablas_helper.php",
        "vendor/diego/helpers/vistas_helper.php",
        "vendor/diego/helpers/html_helper.php",
        "vendor/tcpdf/tcpdf.php"
       ],
"psr-4": {
"CodeIgniter\\": "system/",
        "Diego\\Admin\\": "vendor/diego/admin/",
        "Diego\\Compra\\": "vendor/diego/compra/",
        "Diego\\Foros\\": "vendor/diego/foros/"
}
},

But I don't get them, the helpers, available with Codeigniter4. Is there any way to keep them outside application and system folder. I read the manual but don't understand quite well.

Thank you.