Re: Amir Muwiya’s conversion to Islam
Merit, yes, by the early historians such as Tabari who recorded great amount of data without even giving away his own political/sectarian tendencies (some later historians wrote, as always is the case, by pen and paper provided by the conquerors and the kings). Moreover later developed dogmatic ideas too tainted how the historic accounts were interpreted and defined. One of these ideas is of the absolute goodness of every Sahabi regardless of the idea being in contradiction with the Quran, hadith, tarikh, and intellect on the most elementary of levels. Yes, the idea sounds great but whatever sounds great is not necessarily the haq. History clearly shows that the notion even goes against the conduct of the companions towards each others themselves.
If you do want to study quality objective analysis of the early history of Islam then I would highly recommend ‘The Succession to Muhammad’ by the Oxford University professor, Wilfred Madelung.
All the best in your quest. May Allah help us increase in His knowledge.