Buck PFC dedicated ICs

A look at the most likely place:

https://www.analog.com/en/parametricsearch/11486#/

shows 9 power factor solutions, but none are explicitly 

labelled as buck converters, and a quick look at the

block diagrams doesn't look promising ... but maybe

one or more of them can be configured as a buck,

or maybe there are other solutions lurking in other

parts of the catalog.  Good luck,

Following up, the LT8316 (a flyback controller w/o PFC) shows

how to configure a flyback controller as a non-isolated buck.

This image from page 1 of the data sheet shows the normal

isolated flyback configuration for the chip:

\

and this figure from page 23 of the data sheet shows the non-isolated buck configuration:

Following up, the LT8316 (a flyback controller w/o PFC) shows

how to configure a flyback controller as a non-isolated buck.

This image from page 1 of the data sheet shows the normal

isolated flyback configuration for the chip:

\

and this figure from page 23 of the data sheet shows the non-isolated buck configuration: