Odoo Version 14 community version.

After installing new themes, I cannot find it from the Apps.
I already put unzipped theme folders in /opt/odoo/odoo14-custom-addons (custom path is included in /etc/odoo.conf). Changing ownership to odoo:odoo has been done. Enabling developer mode is already done and then update Apps List. But still, i cannot find the new theme to install. What am i missing?

The logs show:

odoo.addons.base.models.ir_module: ALLOW access to module.update_list on [] to user

Thanks!