Gosh, I just finished catching up on this series yesterday, and I had to look this up myself because the numbering can be a bit confusing. So far, there are three novels in the main Atlee Pine series, and they should be read in the order they were published.
The first one is 'Long Road to Mercy', which came out in 2018. It introduces Atlee, an FBI agent working out of the remote Arizona office, haunted by her twin sister's abduction as a child. The second is 'A Minute to Midnight' (2019), where she returns to her hometown to confront that past. The third and most recent is 'Daylight' (2020), which continues her personal quest and ties into Baldacci's wider universe.
I believe that's it for the dedicated Pine novels. I keep hoping for a fourth, but there hasn't been an announcement yet. I've seen some people count 'Mercy' as book one and include the short story from the 'MatchUp' anthology, but for the core story arc, I'd stick with the three novels. The wait for more is killing me!