I had the same experience. I rarely see any toxic shit on Mastodon compared to what I kept seeing on BlueSky, even after using custom feeds.
I guess it depends on what “toxic” means to everybody. I certainly saw a ton of self-centered hostility towards people who saw the platform differently when I was using Masto more. This place is pretty chill and the one bit of Fedi I still use.
My experience on BS was generally fine so far. Some people really block-happy, which I’m fine with, and during the last migration some of the trolls came over to troll and found themselves summarily banlisted almost universally. I don’t expect them to last super long in there.
But as always with social media, experiences are more variable than anybody intuitively thinks.