I did try that but of course did not see the thread you mention. I had made a backup before I started the update. So I was able just now to get it working by manually updating to PG V18 within the container, and also installing and pointing to a later version of vips in the container:
The site is working now, I suppose.. Then I ran a full rebuild and it succeeded, so hopefully all is well now.
vips-8.18.4
PostgreSQL 18.4
However, I will go in and read the thread you posted in detail, as I have another instance on another machine to update also.
THANK YOU Ed_S!