upgrade Sierra to Monterey and now having Lightroom 6 problems

You can't install LR 6.14 under Monterey because the installer isn't 64-bit. If it is already installed in Mojave or earlier, it may still run but some components might not work.

I run LR 6.14 and a few old 32-bit apps from an external Mojave volume while my main disk is Monterey.

See this article about Lightroom versions: https://en.wikipedia.org/wiki/Adobe_Lightroom

I would contact Adobe for help.

https://helpx.adobe.com/support.html

macOS

MinimumRecommendedProcessorMulticore Intel® processor with 64-bit support or M1 Apple Silicon processor

Operating systemmacOS Catalina (version 10.15)

macOS Big Sur (version 11) or later

Do not see specifics for Monterey listed

I was asking if you are running the latest version. Lightroom CC 2015 (version 6) was released 7 years ago. There have been multiple updates since.

Are you running Lightroom 6.14?