The Mac OS X desktop metaphor does attempt to solve this somewhat, the last application in focus on a particular monitor, is presented within the menubar on that monitor - regardless of whether or not the program is currently been interacted with.
For example: currently I have 4 displays with a program full screen in each, each Menu Bar has the menu options for each program.
All inactive programs present in the menu bars on the other monitors are greyed out - the effect of this can be seen in the linked image (I have minimised the other windows because work business) - https://imgur.com/MM8sQdt
I have Safari Tech Preview [the currently active window], Outlook, iTerm and Firefox (the display for which isn't included in the screenshot because it it's a vertical panel with odd dimensions), open on a monitor a piece.
The Mac OS X desktop metaphor does attempt to solve this somewhat, the last application in focus on a particular monitor, is presented within the menubar on that monitor - regardless of whether or not the program is currently been interacted with.
For example: currently I have 4 displays with a program full screen in each, each Menu Bar has the menu options for each program.
All inactive programs present in the menu bars on the other monitors are greyed out - the effect of this can be seen in the linked image (I have minimised the other windows because work business) - https://imgur.com/MM8sQdt
I have Safari Tech Preview [the currently active window], Outlook, iTerm and Firefox (the display for which isn't included in the screenshot because it it's a vertical panel with odd dimensions), open on a monitor a piece.