The power source needs to be able to temporarily/momentarily provide large portions of the grids energy demands to provide what was needed. Something batteries are typically well suited for.

Mechanical inertia in generators also tends to do well in these situations.

PV panel supply was just not nearly large enough, and if you look at overall PV capacity as a percentage of their grid capacity, it’s pretty obvious it was never going to be enough to stabilize any serious issues.