Above reply by D.I. Johnson is correct for 64-bit Intel.
Intel x86-64 64-bit apps can usually run with the assistance of Rosetta, and Rosetta can be run as far forward as the upcoming macOS 26, but — as I might suspect is arising here — the really old Intel x86-32 32-bit apps are not supported by macOS 10.15 and later and are not supporter by Rosetta at all.
Some 32-bit apps can probably be gotten to work with macOS virtualization or potentially with macOS emulation, on Apple hardware, but older apps and particularly older apps that directly access hardware devices are much more problematic for virtualization or emulation in newer environments.
If the app is already loaded and not working, then use Finder to go to Applications > Utilities, and launch System Information app. Then select Software in the left column, and find your app in the right column, and see if it is shown as 64-bit (“yes”) or 32-bit (“no”). The latter 32-bit apps won’t work on macOS 10.15 and later, and won’t work with Rosetta.
Which apps? Maybe somebody here can take a quick look?