Besides phone screenings, the main piece of the interview ptocess, prior to onsite interviews, was a take-home assignment. It was a pretty thourough set of questions, asking about how to design a particular new system (they provide enough context that I didn't have to ask any further questions to complete it), from vision to architecture diagrams to UI mockups (some areas are optional).
I felt it require a broad set of skills to finish it. I wrote up about 10 pages (no slides), and got invited on site.
On site interviews include 5 or 6 45 minutes interviews, with other PMs, engineers, data scientists, and managers, all asking details about problems they seem to be facing day to day.
Got useful feedback at the end of the process about why i didn't get an offer ultimately.