Check if you are using the lidar_mode with the lower frequency (1024x10 would be less than 1024x20 in terms of publish frequency).
With regard to the timestamp issue it is caused by one of the nodes running as part of the NAV2/SLAM_TOOLBOX being out of sync. Meaning they have different clocks. Use echo to print the header/timestamp of the two topics: /scan (or /ouster/scan) and the /odom topic.
terminal 1) ros2 echo /odom
terminal 2) ros2 echo /scan # or /ouster/scan
Check if the two timestamps between these two topics is within acceptable range (no more than couple milliseconds).
also you can check the timestamp on any other topic that may contribute to the /odom
Check which of these nodes/topics timestamps stand out as out of sync and work on addressing them.
Hope this helps!