Constantine and the impact of Christianity

I found Constantine’s view towards the Church confusing to some extent; I got the impression from the lecture that (in simple terms) while on the one hand he sides against the Donatists’ schism and attempts to persectue them, on the other hand, he perceived the divisions of the Christological heresies and the Arians over doctrinal issues as a trivial issue and for the bishops to decide, hence he presided over the Council of Nicene in 325 to reach a compromise?