Control loop missed its desired rate of 20.0000Hz... the loop actually took 0.1200 seconds

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The first warning occurs because probably your Fixed Frame is set to odom in Rviz. If you change it to the map frame, the warning should go away. If you do not have a map frame, then you can just publish a static transform from odom to map.

The second warning just tells you that you want the control loop to run at 20Hz i.e, 0.05 sec but actually it took 0.12 secs. You can just reduce your control frequency to 5 Hz or use a more powerful computer.

The in place rotation part can happen due to many reasons and you need to provide more information about how you set up your robot. It is most likely not related to the two warnings you mentioned.