If iam installing Odoo 18 community edition in ubuntu as OS, i can upload 3rd Party themes and apps to my system but. After enabeling developer mode with assets and updating apps, i can see each 3rd Party app or theme i have installed, but as a module an not as a app.

Also if iam testing the software for an example, press upgrade on each 3rd party module it says me: 

Invalid Operation

Cannot upgrade module “....... ”. It is not installed.

is there any idea what the problem could be?