bro u shud read the commentary on sahih bukhari by ibn hajar asqalani , also see nasai and tirmidh
esp in relation to zakat , hajj , bayt ul mal , and interest and u will see how muaiwyah changed sunnah and why he is not considered a rightly guided caliph.
esp see the hadith in which miqdam b adi a sahabi has a converstion with muawiyah after assasination of hasan b ali
anyone who introduces bidah in islam is ahle bidah whether rafidah or nawasib. wrt to muawiyah only reason why scholars dont openly criticize them is because he is a sahabi and it gives an opportunity to rafida ( like prince abbas here) to take potshots at all sahaba.