how to use iMac as a monitor for MacBook Pro
How can I use iMac 2019 as a monitor for MacBook Pro M3Pro?
MacBook Pro 14″, macOS 14.5
Question marked as
Those Mac's do not support using the old cabled connection referred to as Target Display Mode.
see > Use your iMac as a display with target display mode - Apple Support
There are some network alternatives like AirPlay or third-party app's like DuetDisplays, but those are to slow for gaming and may not be able to support the full iMac resolution.
My advise it to get an after market external display to use with the MacBook Pro.
see > Use an external display with your MacBook Pro - Apple Support