It’s noteworthy that the incident aircraft was B788. The B787 has a FMC generated approach system called I.A.N. This is in most respects the same as a Vnav approach, except that it generates a (usually) 3 degree approach path out from the runway to the FAF and an inbound course, termed FAC. It is beautifully simple in that normal ILS approach procedures are used, even for a VOR approach, when final approach FMAs would read SPD/FAC/GP.
With known GS fluctuations this crew could have entered the ILS procedure but selected G/S off. This would have generated a hybrid IAN approach in LOC/ GP mode and would have been independent of, and impervious to, G/S fluctuations. Maybe they didn’t understand the system. Further: the B787 has a superb VSD ( vertical situation display) which would have been clearly showing the aircraft flight path directed to a point well short of the runway.