It’s not uncommon for me to see a multi-level building where the ground level (or part of it) is parking and the upper level(s) are retail or commercial. I’ve labeled some entrances as parking=underground, though that’s not really correct in these cases, and others as parking=multi-storey, but since only one level of the building is parking, that doesn’t seem right either.
Is there a better way to tag the entrances (or building part)? Or is it acceptable to use one of these tags as a closest match?
For buildings you better use “level” instead of “layer” according to the wiki.
Level “0” is the lowest level exposed to the open and all other levels are numbered sequently (up or downwards). So if you have to drive down a ramp to reach the parking area it’s level -1 and if the shop is located above the parking it’s level 0 even if you have to take a couple of steps to reach the entrance from the sidewalk.