Unable to install/run Mopidy on RasPi 3

I am following all the steps mentioned here:
https://docs.mopidy.com/en/latest/installation/debian/#debian-install

I am stuck at install mopidy step due to dependencies issue:

    i@raspberrypi:~ $ sudo apt-get install mopidy                                                                                           
Reading package lists... Done
Building dependency tree        
Reading state information... Done
Some packages could not be installed. This may mean that you have
requested an impossible situation or if you are using the unstable
distribution that some required packages have not yet been created
or been moved out of Incoming.
The following information may help to resolve the situation:

The following packages have unmet dependencies:
 mopidy : Depends: python3-tornado (>= 4.4) but 3.2.2-1.1 is to be installed
          Depends: python3-pykka (>= 2.0.1) but it is not going to be installed
          Recommends: gstreamer1.0-pulseaudio but it is not going to be installed
E: Unable to correct problems, you have held broken packages.

I am unable to individually install python3-pykka because of the below error

pi@raspberrypi:~ $ sudo apt-get install python3-pykka
Reading package lists... Done
Building dependency tree       
Reading state information... Done
Some packages could not be installed. This may mean that you have
requested an impossible situation or if you are using the unstable
distribution that some required packages have not yet been created
or been moved out of Incoming.
The following information may help to resolve the situation:

The following packages have unmet dependencies:
 python3-pykka : Depends: sphinx-rtd-theme-common (>= 0.4.3+dfsg) but it is not installable
E: Unable to correct problems, you have held broken packages.

Then I am unable to install sphinx-rtd-theme-common because of some other issue

I also tried installing mopidy using pip install:

pi@raspberrypi:~ $ sudo pip install mopidy
Downloading/unpacking mopidy
  Downloading Mopidy-3.0.2.tar.gz (428kB): 428kB downloaded
  Running setup.py (path:/tmp/pip-build-qxwlR5/mopidy/setup.py) egg_info for package mopidy
    
    no previously-included directories found matching 'docs/_build'
    no previously-included directories found matching 'docs/.doctrees'
Installing collected packages: mopidy
  Running setup.py install for mopidy
    
    no previously-included directories found matching 'docs/_build'
    no previously-included directories found matching 'docs/.doctrees'
Successfully installed mopidy
Cleaning up...

But while running, I see below error:
pi@raspberrypi:~ $ mopidy
-bash: mopidy: command not found

What am I doing wrong here?

Did you try to install on an outdated version of Raspbian? We only support Buster.