Voltage regulators. Voltage regulation technology is extremely advanced as even very small efficiency gains can save billions for hyperscalers. Unfortunately, I don't know of any specific products to share as power isn't my domain. I'm only familiar with the space because we sometimes have to pull telemetry directly from the VRs when doing system level RCAs. Some of our BMCs can do this directly via I2C.
There should be plenty. 48-54 VDC is the standard for OCP powershelf designs. Hyperscalers such as Google have been working for nearly two decades now to eliminate voltage conversion steps. When I left, the power plane within the server PCB ran at the busbar voltage, which could float up to 54VDC. Given this, I'd expect them to convert from 48-54VDC down to 3.3 directly or at most something like 5VDC and then use smaller VRs near components such as ram and cpu.