Slightly off the topic - I am more concerned with the myriad software developers who do not keep up with changes. I have 2 programs on my desktop machine that I use for photo editing all the time, and neither works as an extension with Photos under Catalina. The software company acknowledges it is their problem and they are working on a resolution, but it seems like they should have had access to the beta builds to work this out in advance.
My work around for this issue for the time being, since I still use just one platform/machine (MacBook) to do all my computer work is this...
A couple of years ago, when I first got a GS-911 and needed to use the Windows OS, I purchased an emulator, Parallels, to run Windows within my MacOS.
Now, besides being able to seamlessly jump in and out of my Windows apps, (like GS-911 and my portable DVD player with my Windows based Repair and Service Data disk to copy/paste/print), I have installed an additional complete Operating System in the form of Mac OS 10.14.6, Mojave...my last OS before upgrading to Catalina.
Now I can still have access to any of my apps that appear with a grey "circle with the slash", general prohibition symbol, by just installing them in my Parallels version of MacOS Mojave.
Another program that I doubt will ever have developer support to update it to 64bit is JaVaWa
, that allows me to log onto and manipulate all the files on my Garmin GPS devices. These files are sometimes given obscure names, and this program lists essential files and old map files so you can easily remove large map data files to allow installing larger new files all on the devices internal memory vs splitting it up with part of the map residing on an SD card.
I made an informed decision about upgrading to the 64bit Catalina OS, and am able to still work with all my old 32bit apps in Mojave like before...it's not for everyone, but using an emulator such as Parallels works for me.