"In MacOS Monterey there is a “Erase all contents and settings…” menu item in System Preferences."Unfortunately I don’t have an Intel Mac which runs Monterey, so can’t compare…
"It is listed on my 2020 Intel iMac running Monterey"
Hmmmm....
I -think- that's because the 2020 iMac has the t2 chip. That may be "a requirement" for the "Erase all..." feature to work (even on Intels).
But... 2015 iMac doesn't have it.
What operating system are you running? MacOS/macOS... version...As title states, giving my 2015 iMac 27 to brother. What do I need to do to make it new for him? Please help this is critical for us. Thanks terry