User groups and root access

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I've made a clean install of Fedora 24 about 2 weeks ago. While I'm not new to Linux and I can help myself in most situations there is still much I don't know. I'm moving from Ubuntu to Fedora and, until now, I never had any problems with this until the installation process of Fedora.

When installing Fedora I was asked to set a root password, that I did, and to create an user and here I was faced with the question Do I create a STANDARD or an ADMINISTRATOR account ? I opted for the second option only to later get myself thinking, If I already have root set up, why do I need Administrator privileges ?, so I searched and did this

sudo dnf -y install system-config-users

verefied that the root password was set and then took myself out of Wheel group. According to other questions and guides I read online I should still be able to, for example,

sudo dnf install gimp

or so I thought. The terminal asks me for [sudo] password for mjoao:, only accepts my password, not root ( seems obvious since it has my username there ) and when I enter it, again, obviously, mjoao is not in the sudoers file. This incident will be reported.. Neither su or sudo -i let me log in into root.

I can easily revert the situation, that's not my question. Rather my questions are:

1. Can I use, for a daily basis, a Standard Account ?
2. Can I, whenever I need, log in into root while not being part of wheel group ?
3. If not, where and how can I log in into root when I need to install something or just upgrade the system ?

PS. when I run system-config-users now, even not being part of wheel group, it asks and accepts my password. This I think it's strange. NO LONGER VALID

UPDATE As @florian suggested in a answer bellow, I tried to log in as root using 'su -' and it failed, reporting the same issue than before:

[mjoao@laptop ~]$ su -
[sudo] password for mjoao: 
mjoao is not in the sudoers file.  This incident will be reported.

I also ran 'groups', that only returned me with my own username.

[mjoao@laptop ~]$ groups
mjoao