How to set display of a single component in Joomla admin panel for a single user?

Question

Joomla

I just can not master, I feel, a simple task. I created a new user on Joomla 3.x, created a new user group for it. If you immediately go to the admin panel under this user, the menu will be empty, nothing is attached. BUT! I don't understand how can I specify a specific item in the menu that will be available to this user? I thought that this is configured through the "Menu -> All menu items" and select the type "Control Panel", but it is empty there, although I make the settings under the admin. I guess that's not how it's done. I thought that it was possible to do it through the general settings, when a list of all components falls out on the left, and when you click on it, you can go to the desired component and select the "Permissions" tab, but no, there are things of the access level to the component itself, but not its presence on the menu.
The second problem is that I can't figure out how the rights of user groups to something are redefined. For example, I have a component, I want to disable "Component Management" for it, I select "Deny", but "Allowed (Super Administrator)" green with a lock is displayed to the right. I don’t understand where this opportunity is blocked by the rights above, given that the group that I created and want to configure is under “Everyone”, in theory, only “Everyone” needs to be allowed, but even it has “Inherited”, while to the right, "Not allowed (inherited)" is displayed in red. Some lunatic...

Answer 1

I thought that it was possible to do it through the general settings, when a list of all components falls out on the left, and when you click on it, you can go to the desired component and select the "Permissions" tab, but no, there are things of the access level to the component itself, but not its presence on the menu.

That's right - you need to allow access to the component. Then it will appear in the menu item. This right is "Manage component".
You also need to add this user group to the Special access level. It's in "Users" > "Access Levels".

I want to disable "Component Management" for it, I select "Deny", but to the right it displays "Allowed (Super Administrator)" in green with a lock.

You can't disable anything as a super admin.

I don’t understand where this opportunity is blocked by the rights above, given that the group that I created and want to configure is under “Everyone”, in theory, only “Everyone” needs to be allowed, but even it has “Inherited”, while to the right, "Not allowed (inherited)" is displayed in red. Some lunatic...

Some kind of porridge. If it says "Not allowed (inherited)", then it means that there is a ban.