Hot take Itachi and Kakashi are stronger than Obito and Madara. Obito and Madara both have Hashirama Cells Meaning they never experienced Any eye fatigue literally spammed ems abilities. While Kakashi and Itachi arguably the entire show were nerfed. Itachi never turned his eyes off he never risked being off guard. And still blew through Jutsu. Kakashi had to cosplay as a pirate to keep his sharigan off. Effectively only having one eye at all times.