Update: connected to the serial console, and this seems to be some of the relevant details:
init_ota_log /mnt/ota_log
Create log file at /mnt/ota_log/ota_20230113-025911.log
OTA_LOG_FILE=/mnt/ota_log/ota_20230113-025911.log
init_exception_handler /mnt /mnt/ota_log/ota_20230113-025911.log 1
ota_validate_payload /mnt/ota_work jetson-agx-xavier-devkit R32-7
Validating OTA payload
ota_check_rollback /mnt/ota_work jetson-agx-xavier-devkit R32-7
Invalid target board jetson-agx-xavier-devkit
Failed to run "ota_check_rollback /mnt/ota_work jetson-agx-xavier-devkit R32-7"
OTA retry count file is at /mnt/ota_retry_count
OTA retries 1 time(s)
Reached OTA max retries (1 times)
No idea why jetson-agx-xavier-devkit isn’t a valid board, that is what you’ve got in the documentation here, and it is a devkit module.