This might sound like an unbelievably naive Question and still would it be impossible, or problematic, to rip the guts out of a modern 24" iMac, and re-house them in an 'ancient…' 27" case, in order to use the 27" screen?
iMac 27″
No you can not mix and match like that, because everything including the connections are different.
If you have a 24" iMac, you can connect a 27" aftermarket external display to it.
Connect an external display to your iMac - Apple Support
If you get a new Mac mini, you can connect 1 or 2 27" aftermarket external displays to it.
Connect a display to Mac mini - Apple Support
The settings for the 24" iMac's built-in display, are not the same as they were back in 10.13.6 High Sierra.
ref: Change your Mac display’s resolution - Apple Support
Thanks, Den.
Please see Phil, above
👍 I also upvoted Phil0124's reply.
1 speaker not working his stopped please working
Yes
iMac displays: can a 'modern…' 24" model drive an 'ancient…' 27" screen?
