Working now. Please disregard. Added TerminalManager to the exising singleuser helm chart MappingKernelManager config. Timeout and interval values are really low for testing.
singleuser:
extraFiles:
mountPath: /etc/jupyter/jupyter_notebook_config.json
data:
TerminalManager:
cull_inactive_timeout: 30
cull_interval: 60
MappingKernelManager:
cull_idle_timeout: 30
cull_interval: 60
cull_connected: true
cull_busy: false