Catalog froze during upgrade

[MamaRona]

I'm trying to update to LR Classic 9.2 from an older version so I had to update the catalog as well.  It was all going fine initially, but then the catalog update froze while adding depth information.  I hit the cancel button after waiting and now it's frozen on cancel and Lightroom never opened.  I'm worried that if I "Force Quit" I will corrupt the catalog since it was in the middle of an update.  The last time I tried to update several months ago was a total disaster resulting in hours on the phone with Adobe and finally  reverting to an older version of LR Classic.  I decided to try this later update in hopes the bugs had been worked out and that it would help me have a faster workflow. My computer is a 2019 MacBook Pro using Mojave 10.14.6 What should I do? 

[cmgap]

Before you do anything - do  you have a current backup of your Lightroom Catalog?

It appears that you don't have a choice but to force quit Lightroom, restart your computer and open Lightroom. If  you've run into problems updating your catalog before do  you remember why? Where are your originals stored? How many images do you have in  your catalog?

[MamaRona]

I do have a recent backup as I made one just before attempting the upgrade.  Since I posted I was able to restart the upgrade.  Unfortunately now even though I was able to successfully upgrade both the catalog and the Lightroom version to 9.2, now the whole system is unusably slow - which is what occurred last time I attempted an upgrade.  I've gone through every tutorial on how to speed up Lightroom to no effect.  I've rebooted the computer twice and restarted Lightroom multiple times.   It works at a normal speed (or a little slow but still usuable) for a few minutes, and then gets slower and slower until it's essentially frozen - both in Library and Develop modules.  I have not tried to import any new photos since the upgrade.  I have room on my hardrive and while I do have many images, they are stored on an external network drive.  There are 294,000 photos in my catalog.  I know that's a lot but everything was running fine on the older version of LR. I need this to work for my photography business.  Specs on my MacBook Pro:  2.4 Ghz Intel Core i9, Memory -32 GB 2400 MHz DDR4, Graphics - Radeon Pro 560X 4 GB, Intel UHD Graphics 630 1536 MB

Any idea why this is happening and what I can do?