The main warning is this one:
[ WARN] [1618088334.410202467, 48.557000000]: /rtabmap/stereo_odometry: Did not receive data since 5 seconds!
Make sure the input topics are published ("$ rostopic hz my_topic") and the timestamps in their header are set. Parameter
"approx_sync" is false, which means that input topics should have all the exact timestamp for the callback to be called.
/rtabmap/stereo_odometry subscribed to (exact sync):
/zed2/left/image_rect_color \
/zed2/right/image_rect_color \
/zed2/left/camera_info \
/zed2/right/camera_info
you should check if those topics are published:
rostopic hz /zed2/left/image_rect_color \
/zed2/right/image_rect_color \
/zed2/left/camera_info \
/zed2/right/camera_info