First time posting, so I will make this brief but it is such an interesting topic. I only know about the effect of estrogen on my "cis male" self a couple years ago.
As has already been suggested, I think you can divide up the effect of estrogen into 1) the effect of adding estrogen and 2) the effect of subtracting testosterone. Because both happen simultaneously I think it can be a bit difficult to sum up just what happens.
For me, the loss of testosterone had a clear drawback and a clear benefit. The drawback was that it became harder to hyperfocus on work problems. The benefit was that all that toxic aggro that accompanies the male identity started to melt away. I can't quite put into words what the process of lightening up/losing the fear and anger of my male self has been like...
So darn wonderful that I am tearing up just thinking about it? Yes, something like that.
Now what estrogen seems to do, for me, is rather than just removing negative emotions, it seems to awaken an interest in other people that I didn't have before. Basically, for me I have found that I have been able to begin a journey towards becoming an actively more empathetic person. Not just a functional "enlightened self-interest" sort of empathy - I scratch your back because then you'll scratch mine, etc. I actually find that I carry around more interest in how other people are feeling.
On both the reduction of aggressive, fearful experience and the enhancement of empathetic, sensitive experience I am absolutely sure that the little blue pill just provides the first step, "clearing the stage" for....a different, hopefully better, way of being.