Personally I knew it was wrong to unnecessarily cause suffering long before I went vegan, so I’ve been much happier since cutting it out of my life. I get unreasonably happy about making new dishes or desserts now, without that niggling thought of the animals that suffered or died for it and the cognitive dissonance of trying to ignore it and still care about animals.

I do think "at peace" is a good way of putting it. In theory, I'm of the opinion that if we treat animals as peers, then it's fine to trade e.g. shelter for foods.

In practice however, this is virtually impossible to actually do. You pretty much have to care for the animals yourself to know they're not being mistreated, and especially for dairy, you're not going to get a lot out of it, without exploiting the animals.

Whether eating the unborn child (or period, or whatever you want to call it) of your peer, is really something you would do, that's a whole 'nother story.

So, in effect, I feel like I was lying to myself when I was still vegetarian, and it was certainly not a moral conviction that held me there, but rather social expectations.
That was an inner conflict, which I was repressing rather than resolving. Now that I'm vegan, this conflict is gone.

holy shit, yeah.

It's hard to be precise about the causality with so much subjectivity.

Nahh. I'm totally category 1.

Both !
I feel a lot better since going vegan, in my body and in my head, I feel like i live a bit more by my values and it's great. I also think anti-speciesism has been affecting my engagement in actively doing some good in my communities (whether it's about animals, people or else)
But by becoming vegan, I had to overcome the cognitive dissonance that had been with me since I was a child, the very same one created by the agri-food lobbies to separate the product from the animal. And that has brought these two ends of the chain back together, showing that one simply cannot exist without the other. And by getting rid of this cognitive dissonance, I am more exposed to the fact that the majority of the rest of the world continues to kill, torture and so on, I am more sensitive to it for sure
So I'd say both