I am planning on designing a PMIC @User. Starting out with something like a ~5V to VCore buck converter (with external inductor of course) that can power the digital logic in the PDK and be integrated into other designs. A fair number of commercial MCUs have something similar nowdays.

Why not high-frequency on-chip resonant power converters 😉

I am interested in working on some resonant switched capacitor stuff eventually. But IC design is pretty complex, I think its worth initially focusing on some basic DC/DC converter for the first free shuttle. Less to go wrong and a design that is more generally applicable to other projects will be more likely to get chosen if there is more projects than slots.