I am running the example from Jan Procházka on ESP32-C6.
After deep sleep exit, the commissioning time is very long, impacting device battery life.
Is there a way to improve this (using RTC memory for example) ?

Here are some traces with Zigbee timeout lightly increased Zigbee.setTimeout(20000)
15:00:26.192 -> Starting Zigbee
15:00:26.192 -> [ 899][D][ZigbeeCore.cpp:145] zigbeeInit(): Initialize Zigbee stack
15:00:26.224 -> [ 943][D][ZigbeeCore.cpp:152] zigbeeInit(): Register all Zigbee EPs in list
15:00:26.224 -> [ 945][I][ZigbeeCore.cpp:160] zigbeeInit(): List of registered Zigbee EPs:
15:00:26.224 -> [ 945][I][ZigbeeCore.cpp:162] zigbeeInit(): Device type: Temperature Sensor, Endpoint: 10, Device ID: 0x0302
15:00:26.224 -> [ 959][V][ZigbeeCore.cpp:379] esp_zb_app_signal_handler(): ZDO signal: ZDO Config Ready (0x17), status: ESP_FAIL
15:00:26.224 -> [ 959][I][ZigbeeCore.cpp:241] esp_zb_app_signal_handler(): Zigbee stack initialized
15:00:26.224 -> [ 960][D][ZigbeeCore.cpp:242] esp_zb_app_signal_handler(): Zigbee channel mask: 0x07fff800
15:00:28.574 -> [ 3286][W][ZigbeeCore.cpp:276] esp_zb_app_signal_handler(): Commissioning failed, trying again...
15:00:31.387 -> [ 6114][W][ZigbeeCore.cpp:276] esp_zb_app_signal_handler(): Commissioning failed, trying again...
15:00:34.233 -> [ 8941][W][ZigbeeCore.cpp:276] esp_zb_app_signal_handler(): Commissioning failed, trying again...
15:00:37.050 -> [ 11768][W][ZigbeeCore.cpp:276] esp_zb_app_signal_handler(): Commissioning failed, trying again...
15:00:39.861 -> [ 14595][W][ZigbeeCore.cpp:276] esp_zb_app_signal_handler(): Commissioning failed, trying again...
15:00:42.706 -> [ 17422][W][ZigbeeCore.cpp:276] esp_zb_app_signal_handler(): Commissioning failed, trying again...
15:00:45.516 -> [ 20249][W][ZigbeeCore.cpp:276] esp_zb_app_signal_handler(): Commissioning failed, trying again...
15:00:48.385 -> [ 23111][I][ZigbeeCore.cpp:248] esp_zb_app_signal_handler(): Device started up in non factory-reset mode
15:00:48.385 -> [ 23112][I][ZigbeeCore.cpp:261] esp_zb_app_signal_handler(): Device rebooted
15:00:48.385 -> [ 23113][V][ZigbeeCore.cpp:527] setNVRAMChannelMask(): Channel mask set to 0x00000800
15:00:48.385 -> [ 23114][D][ZigbeeCore.cpp:512] searchBindings(): Requesting binding table for address 0x6511
15:00:48.385 -> [ 23115][D][ZigbeeCore.cpp:452] bindingTableCb(): Binding table callback for address 0x6511 with status 0
15:00:48.385 -> [ 23116][D][ZigbeeCore.cpp:455] bindingTableCb(): Binding table info: total 3, index 0, count 3
15:00:48.385 -> [ 23116][D][ZigbeeCore.cpp:465] bindingTableCb(): Binding table record: src_endp 10, dst_endp 1, cluster_id 0x0405, dst_addr_mode 3
15:00:48.385 -> [ 23117][D][ZigbeeCore.cpp:482] bindingTableCb(): Device bound to EP 10 -> device endpoint: 1, short addr: 0x0000, ieee addr: 1C:C0:89:FF:FE:CE:XX:XX
15:00:48.385 -> [ 23117][D][ZigbeeCore.cpp:465] bindingTableCb(): Binding table record: src_endp 10, dst_endp 1, cluster_id 0x0001, dst_addr_mode 3
15:00:48.385 -> [ 23118][D][ZigbeeCore.cpp:482] bindingTableCb(): Device bound to EP 10 -> device endpoint: 1, short addr: 0x0000, ieee addr: 1C:C0:89:FF:FE:CE:XX:XX
15:00:48.385 -> [ 23119][D][ZigbeeCore.cpp:465] bindingTableCb(): Binding table record: src_endp 10, dst_endp 1, cluster_id 0x0402, dst_addr_mode 3
15:00:48.385 -> [ 23119][D][ZigbeeCore.cpp:482] bindingTableCb(): Device bound to EP 10 -> device endpoint: 1, short addr: 0x0000, ieee addr: 1C:C0:89:FF:FE:CE:XX:XX
15:00:48.385 -> [ 23120][D][ZigbeeCore.cpp:503] bindingTableCb(): Filling bounded devices finished
15:00:48.385 -> Connecting to network
15:00:48.385 -> Successfully connected to Zigbee network