Given that originally, the plan was to reach 100 with a bunch of crossovers, and go monthly, and several other things, and we know that plans have changed at least twice since then, I have no idea what Tynion's run is really going to be anymore. I personally hope he gets at least 20 issues to make up for his Tec run getting cut short. And if he gets to write until 135, which will be Batman #900, that would be even cooler.
I recently heard a theory that 5G, rather than a linewide shift, is probably more like an event (similar to DC One Million) which makes a lot of sense.