Using late 2015 iMac (5K Retina?) as a screen only workaround

Anyone know a good workaround for the above with a mac mini M2?

Otherwise a suggestion for an affordable monitor for office tasks.

Have also looked at (but not tried) forcing a later OS onto the no longer supported iMac, anyone done this with any success?

Cheers

Target Display mode the old way of doing this only works up to 2014 iMac according to this article. Something called Luna could be an option though.

Thanks, will have a look.