This may be of some help, so Williamson had an interview at Comicpop and besides talking about Birthright, Flash, and Robin he brought up Infinite Frontier and how he described it was that it’s not an event as we have seen it before, it’s more a slow mystery while also going into characters opinions and motives after surviving multiple reality rewriting events, however the big thing is that it will also serve as setup for an actual big event as we know it next year.
He talks about Darkseid setting up plots, Bones being “hey this is weird all that’s happened right”, Chase investigating the Justice League a little, and Barry Allen dealing with weird Multiverse stuff. Kind of like exploring the dc universe after a big event like death metal has happened.