Why isn't Gazebo publishing on the /odom topic on ROS2?

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Hey all! I'm having some problems with Gazebo. I'm using ROS2 foxy on UBUNTU 20.04.5 LTS with Gazebo installed via ros-foxy-gazebo. I made an URDF model on a differential drive robot, with a launch file to run gazebo and spawn the robot. Even though, when launching the file, it appears on the terminal that the diff_drive is advertising the /odom and publishing the tf between odom frame and base_link, i cannot find the frame odom in RVIZ2. Moreover, when echoing the /odom topic i have no results. Finally, in the view_frames the odom frame doesn't appear. I guess that i did the correct launch file with the diff_drive control plugin and the good parameters. Here below the files. Launch file:

import os

from ament_index_python.packages import get_package_share_directory


from launch import LaunchDescription
from launch.actions import IncludeLaunchDescription
from launch.launch_description_sources import PythonLaunchDescriptionSource

from launch_ros.actions import Node


def generate_launch_description():

    # Include the robot_state_publisher launch file, provided by our own package. Force sim time to be enabled
    # !!! MAKE SURE YOU SET THE PACKAGE NAME CORRECTLY !!!

    package_name = 'package_test'  # <--- CHANGE ME

    rsp = IncludeLaunchDescription(
        PythonLaunchDescriptionSource([os.path.join(
            get_package_share_directory(
                package_name), 'launch', 'rsp.launch.py'
        )]), launch_arguments={'use_sim_time': 'true'}.items()
    )
# Include the Gazebo launch file, provided by the gazebo_ros package
gazebo = IncludeLaunchDescription(
    PythonLaunchDescriptionSource([os.path.join(
        get_package_share_directory('gazebo_ros'), 'launch', 'gazebo.launch.py')]),
)

# Run the spawner node from the gazebo_ros package. The entity name doesn't really matter if you only have a single robot.
spawn_entity = Node(package='gazebo_ros', executable='spawn_entity.py',
                    arguments=['-topic', 'robot_description',
                               '-entity', 'my_bot'],
                    output='screen')

# Launch them all!
return LaunchDescription([
    rsp,
    gazebo,
    spawn_entity,
])

Gazebo plugin:

<?xml version="1.0"?>
<robot xmlns:xacro="http://www.ros.org/wiki/xacro"  name="robot">

   <gazebo>
        <plugin name="diff_drive" filename="libgazebo_ros_diff_drive.so">
            <!-- Wheel info-->
            <left_joint>left_wheel_joint</left_joint>
            <right_joint>right_wheel_joint</right_joint>
            <wheel_separation>0.35</wheel_separation>
            <wheel_diameter>0.1</wheel_diameter>

            <!-- Limits-->
            <max_wheel_torque>200</max_wheel_torque>
            <max_wheel_acceleration>10.0</max_wheel_acceleration>

            <!-- Output-->
            <odometry_frame>odom</odometry_frame>
            <robot_base_frame>base_link</robot_base_frame>

            <publish_odom>true</publish_odom> 
            <publish_odom_tf>true</publish_odom_tf> 
            <publish_wheel_tf>true</publish_wheel_tf> 

        </plugin>


     </gazebo>

</robot>

URDF file:

<?xml version="1.0"?>
<robot xmlns:xacro="http://www.ros.org/wiki/xacro" >

    <xacro:include filename="inertial_macros.xacro"/>

    <material name="white">
        <color rgba="1 1 1 1" />
    </material>

    <material name="orange">
        <color rgba="1 0.3 0.1 1"/>
    </material>

    <material name="blue">
        <color rgba="0.2 0.2 1 1"/>
    </material>

    <material name="black">
        <color rgba="0 0 0 1"/>
    </material>

    <!-- BASE LINK -->

    <link name="base_link">

    </link>


    <!-- CHASSIS LINK -->

    <joint name="chassis_joint" type="fixed">
        <parent link="base_link"/>
        <child link="chassis"/>
        <origin xyz="-0.1 0 0"/>
    </joint>

    <link name="chassis">
        <visual>
            <origin xyz="0.15 0 0.075"/>
            <geometry>
                <box size="0.3 0.3 0.15"/>
            </geometry>
            <material name="white"/>
        </visual>
        <collision>
            <origin xyz="0.15 0 0.075"/>
            <geometry>
                <box size="0.3 0.3 0.15"/>
            </geometry>
        < ...