You are definitely pointing me in the right direction and thought that I was there...but then OMGosh, I ran ncam and got the error....No module named linuxcnc. I then looked under the Applications pull down menu and sure enough linuxcnc was not installed. So as you suspected, obviously I must have downloaded the wrong iso but where do I go to get the right iso? I downloaded DVD-1 from the address below. I assumed that this was the standard Buster and not the LinuxCNC distro.
cdimage.debian.org/debian-cd/current/amd64/iso-dvd/
[ISO] debian-10.7.0-amd64-DVD-1.iso
Anyway this may not matter now since I don't have the linuxcnc module installed, but to successfully clear all of earlier error messages I did the following.
Open Applications > System > Synaptic Package Manager
Select everything starting with "gtk" for install (I agree this was obsessive but hey it worked!

)
Opened a terminal and typed
sudo apt-get install python-tk
sudo apt update -y
sudo apt upgrade -y
ncam
then the error message....No module named linuxcnc....darn it!
With just a little more coaching & help I know I can get this working in Buster.
Can you please point me in the right direction for the right iso download for both the AMD64 format and the i386 format?
Thank you for helping me with this.
Barry