I just found out that some apps that I uninstall from my tablet are still listed in "all apps" section by my device, although marked as "not installed":
Apps List (click image for larger variant)
How can I fully remove them? Please note that those are not system apps or pre-installed apps by manufacturer.
Settings -> Apps -> select your app tap on menu button (3 dots) -> Uninstall for all users
If you have multiple users on your tablet, this means that the apps are installed by another user, and therefore take up space without being installed under your user account. Just open the other accounts and uninstall the apps from there.
In the menu there is an option to uninstall for all users so you don't have to loging in to each user on the main.
