That code is for editing
[default]DPB/PI05051/CMD/OVR.Enabled when the tag already exists. If it doesn’t already exist, system.tag.configure will create the base path in folders as you note because it doesn’t have any information to tell it to do something else with the levels above.
To create this structure including UDT with system.tag.configure, you’d need to first call system.tag.configure to create the UDT instance
PI05051 at base path
[default]DPB, and then call it again as above to configure the override on
[default]DPB/PI05051/CMD/OVR.Enabled (although as noted above, there seems to be a bug with setting overrides via system.tag.configure in 8.0.9; using system.tag.writeAsync/Blocking works).
EDIT: The second parapgrah above is incorrect. See this post below for the correct way to set overrides at various nesting levels with system.tag.configure (you can create the tag and set overrides at various nesting levels all in one system.tag.configure call), and see this post further below for a function that builds the nested structure and sets a nested property override based on supplied path.