macOS update 10.14.6 Issues

Ok, after 2 weeks of struggle, it has been determined via Disk Utility and other diagonoze method from MacRumor forum people, that the original internal HDD has gone bad and corrupted. Even having difficulty backing up the system before I replace the HDD with a newly purchased SSD. Time Machine took 5 days to backup 250+GB to an external USB 2T Toshiba. Gave it up, use the trial version of Carbon Copy a few times, before it was finally successful and was able to boot from the External USB Toshiba, at that point the iMac is finally ready to receive the new SSD. Bought the OWC kit, unfortunately, the kit didn't match exactly the internal spec, only after I open up the iMac. THe bracket is only a 2.5 inch instead of 3.5, no room to place the temperature sensor. finally installed the new SSD, restore the Carbon Copy backup, boot it up the first time. macOS Mojave 10.14.6 finally updated properly and was done quickly due to the new SSD.

I am exhausted from this 2 week long process and ready to tkae a break. I learned a lot and thanks to many helpful people. I need a vacation... Not ready to goto new macOS Catalina, yet, there is just too many back feedback and review with the new Catalina, so many are disappointed with it. I decided to wait. Apple quality surely has not been up to PAR with macOS updates like in the past. I will caution those who has not backup their system regularly, BACKUP your stuff regularly.

P.S., the System Preference->software update still does not allow me to upgrade to Catalina by default...

This is not over, yet...

Thanks!