Different scales (or resolutions) for different apps in the same screen?
If I am understanding you correctly one app seems larger than another app?

Unfortunately it is not possible to adjust the resolution for an individual app. On macOS (and Windows too) the resolution of the screen is set on a screen by screen basis and can't be set for a specific app.

In System preferences > Displays

You can adjust those parameters.

If you have more than one display you could adjust the resolution on each display and keep those particular apps on the screen they look best on.