How do I limit information being applied only to Network Administrators?

TL;DR;
I am building a multisite for a City Council where every member will have its own subdomain.
In one of the plugins, I want to limit some menu options to be shown only to the users with the network admin role.

I found this from almost 5 years ago but it doesn’t work.

What do I need to change? What would be the best way to first check that the user has the network admin role?

Thanks,

AG