Big Business 14 supports macOS Monterey as the minimum system for regular use.
Big Business 14 can run on macOS Big Sur, temporarily, to help with your Upgrade. You can put in Big Business 14, then work on replacing computers below Monterey.
Google, Monterey Install, to find it in the App Store to see if it installs on computers. You do not need to put Ventura or Sonoma on older computers for Big Business 14.