There is a saying about topics of discussion.

There are those who talk about people.
Others who talk about things.
And a few who talk about ideas.

I struggle to hold any interest in talking about people.
I spend more time talking about things.
But, I gravitate toward talking about ideas.

Unfortunately, most conversations I witness are about people.

If I was alone with a single person, it that person was interest in 2 or 3 above, I'd be OK. I'd fail at 1.

I am not good at idle conversation, mainly because I do not see much purpose to it.

But, if the conversation is task or activity focused, I'd probably be OK.

But, I don't see flat affect impacting conversation that much. But, that can just be me because I have never been one to talk about feelings. I also do not get a sense of self from my ability to hold a conversation.