Apparently since macOS Catalina 10.15 Mac disabled support for 32-bit apps?
How can Steam games like Portal 2 be played on MacBooks that have been keeping up with macOS updates?
In my case I'd like to do this on Intel MacBooks from 2015.
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I rolled my 2018 Mac Mini back to Mojave.
In hindsight, I wouldn't have done that (I lost a few factory-loaded apps). I would have gotten a very fast USB thumb drive and put a Mojave OS (and the games) on that. That particular drive is what I used for my gaming until I got a slightly faster USB-C drive. Apple explains how to get previous versions of macOS, here.
MacWorld has a procedure on that. You might need to use a partition on a second thumb drive to install the previous version OS X installer and then reboot to that thumb drive for the installation proper in case the 10.14 installer doesn't want to run under Monterey.