System hangs upon shutdown

r8152 seems to be a USB Ethernet controller. Is this part of the system please?

Yes

If you pull it out, then shutdown, does it shutdown OK?

No....Its still hangs and I have to press button to do it

Do you initiate the shutdown with mouse-click on the top right icons and selecting the shutdown icon, or with the "sudo shutdown" command?
Do sou see the same behavior also with the other way?
Do you see the same behavior when you initiate a reboot?

Hello Manfred Hampl,

    Yes, with mouse click on the top right icons.
     Yes, it behaves the same both with reboot and/or shutdown.

I tried to shutdown again and this time it took almost 10mints to shutdown.

"I tried to shutdown again and this time it took almost 10mints to shutdown."

So the system does shut down, but only with several minutes delay?

Suggestion for diagnostics:

Your log shows two different messages:
[7921.330474] systemd-shutdown[1]: could not detach DM /dev/dm-0: Device or resource busy
[7924.300025] r8152 4-2.1.2:1.0 enx3ce1a1c5bfec: Tx timeout

What happens if you deactivate the network first and then do the shutdown
https://linuxhint.com/ubuntu-enable-and-disable-the-network-interface/

Which messages are then shown in the system log?

What log files do you need?

I would expect the most useful information at the end of the systemlog of the previous session, /var/log/syslog.1.gz

I didn't find syslog.1.gz but syslog.1
Jul 12 00:00:01 systemd[1]: Started CUPS Scheduler.
Jul 12 00:00:01 systemd[1]: cups.socket: Succeeded.
Jul 12 00:00:01 systemd[1]: Closed CUPS Scheduler.
Jul 12 00:00:01 systemd[1]: Stopping CUPS Scheduler.
Jul 12 00:00:01 systemd[1]: Listening on CUPS Scheduler.
Jul 12 00:00:01 systemd[1]: Started CUPS Scheduler.
Jul 12 00:00:01 systemd[1]: Started Make remote CUPS printers available locally.
Jul 12 00:00:01 falcon-sensor[909]: CrowdStrike(6): AFLAGS updated to 0. error_log is now OFF
Jul 12 00:00:01 falcon-sensor[909]: No traceLevel set via falconctl defaulting to none
Jul 12 00:00:01 falcon-sensor[909]: LogLevelUpdate: none = trace level 0.

Unfortunately that output does not help identifying the root cause of your problem.

Can you please let me know what logs you need?

I do not need any log, but you should try finding hints why the shutdown does not correctly happen.
I suggest that you dig through the logs in /var/log/
Look for time codes around the tome when you tried shutting down.

Hello Manfred Hampl , Can you please tell me whats happening when rebooting the system.....its something related to postgresql

Jul 12 01:52:29 nb-gk-lin-0001 systemd[3761]: run-user-278046-gvfs.mount: Succee
ded.
Jul 12 01:52:29 nb-gk-lin-0001 tracker-store[2069791]: Received signal:15->'Term
inated'
Jul 12 01:52:29 nb-gk-lin-0001 tracker-store[2069791]: OK
Jul 12 01:52:29 nb-gk-lin-0001 systemd[3761]: obex.service: Main process exited,
 code=exited, status=1/FAILURE
Jul 12 01:52:29 nb-gk-lin-0001 systemd[3761]: obex.service: Failed with result '
exit-code'.
Jul 12 01:52:29 nb-gk-lin-0001 systemd[1]: Stopped PostgreSQL RDBMS.
Jul 12 01:52:29 nb-gk-lin-0001 systemd[3761]: tracker-store.service: Succeeded.
Jul 12 01:52:29 nb-gk-lin-0001 systemd[1]: Stopping PostgreSQL Cluster 12-main..
.
Jul 12 01:58:44 nb-gk-lin-0001 systemd-modules-load[597]: Inserted module 'lp'
Jul 12 01:58:44 nb-gk-lin-0001 systemd-modules-load[597]: Inserted module 'ppdev
'

This is a completely different topic and should better be dealt with in a separate question.

From the part from the logs I cannot see anything wrong with PostgreSQL. Are you using it? Do you expect it to run?
Are there more lines than just those two for PostgreSQL in the logs?

I see a failure message from obex (related to bluetooth)
For that I suggest checking the command
systemctl status obex.service

GRUB_CMDLINE_LINUX_DEFAULT="intel_pstate=enable quiet splash acpi=force" fixed the issue for me