DisplayEntityBuilderTool‎
Warning: This plugin requires version 1.19.4 or higher as it uses Item Display Entity for the upright slab.

Test Version

• 1.20.2

Commands

• /standslab‎ Open stand-slab selection menu
• /standstairs‎ Open stand-stair selection menu

Permissions

Code (Text):

  displayentitybuildtool.gui.slab:
    default: op
  displayentitybuildtool.gui.stairs:
    default: op
  displayentitybuildtool.place:
    default: op
  displayentitybuildtool.break:
    default: op

How to use
Hold the bone and shift with the left click (or right click) to open the upright-slab selection menu to select the upright-slab. Hold the bone with the right click to place it, and the left click to destroy it.