Installing a lightweight admin theme with white labelling capabilities

I need to find a wordpress them that will remove the wp mentions, logos, help, widgets, etc and redesign the aspect.
So far what I have tested, are to heavy in ressources. checking with P3 makes these themes or softwares like AG, too heavy and pages are taking twice time to load...
Do yo have a light weigh solution ?
Even admin menu editoir is very heavy, so I need a solution for this as well..
Best regards,