What is the current consensus on how to map sidewalks when they are only separated from the street by a curb?
Last I heard more than one year ago was the two main systems.
- tags at the street unless clearly separated.
on highway=*, sidewalk=both + sidewalk:surface= etc.
- separate ways following centerline of the sidewalks with individual tags. in almost any case.
highway=footway or similar + surface= etc.
Both systems sort of existed and were used by different peoples, some country communities preferred one or the other and converting one to the other was discouraged for the time being. Have there been any developments since Covid?
I prefer to map sidewalks separately, so I can add more info about width, surface and smoothness of the sidewalk, without clogging the way.
I prefer separate sideways too. It makes much more sense when connecting them to other footways
https://wiki.openstreetmap.org/wiki/Sidewalks
This page has all the answers you need.