When interviewing users many UXRs would start the session with small talk. I guess the underlying assumption is that (1) we need small talk to kick off the conversation and that (2) rapport suffers if we skip the small talk.
I think non of these are true.
We need small talk when we want to start a conversation with someone to who we don't have any reason to talk. For example when you see an attractive stranger at a bus stop and you want to talk to them but you have no excuse to do so, then you need to fabricate a reason: you ask them what time it is; ask them about the bus schedule, etc. That is going to be the conversation starter.
But UXRs have a valid reason to talk to the participant. The participant already agreed to discuss the topic with us.
So small talk is not necessary to kick off the conversation. It may even come off as awkward or disrespectful - after all, we are wasting our precious time together on topics that neither of us is genuinely interested in. Why not cut to the chase?
Small talk is not necessary for rapport either. Rapport is trust. Trust comes from the Researcher being respectful, open-minded, and non-judgmental. In my experience, these attributes become evident to the participant after our first few sentences, even without any small talk.
Hence I suggest that you don't stress too much about small talk. If the participant initiates it, go with it. If they don't, just skip it.