This is a great question; I think of the Hornsea use case. Although the power transferred through renewables to the system is through power electronics, power electronics typically do not provide an inertial response to the grid. An example of this was August 9, 2019, from the Hornsea Windfarm in the UK.
The Hornsea Project is an offshore wind farm located off the Yorkshire coast within the Hornsea Zone in the southern North Sea. During the evening rush hour, London and surrounding areas suffered a widespread power outage Friday, August 9, 2019. During the blackout, renewable generation was a significant portion of the overall contribution to the transmission system. Unfortunately, the lack of inertia coupled with improper settings on the wind farm did not correctly respond to the dip in frequency from the transient event. As a result, a cascading blackout occurred that dropped power to hundreds of thousands of people.
With renewables that have transient power output and power electronic sources, becoming the primary source of generation to the grid, grid flexibility is key to not simply having an after-action review after a blackout but to prevent outages in the first place. Dynamic controls coupled with a state estimator and real-time power flow tool will allow the grid to maintain a two-way power flow while assuring the generation matches the demand.