Your statement that Apple have deliberately removed the feature is incorrect. I simply pointed out for you and whomever else may be reading this thread that the feature is still available in macOS Sequoia. Neither of the two methods I posted for troubleshooting the problem has been disabled. Clearly the function is not working properly on your machine.
You've stated neither which Mac mini you have (there have been at least 19) nor what macOS version it's running, so I'll assume the new M4 and Sequoia. Please correct me if I'm wrong.
You also haven't told us what you've done to troubleshoot the problem, and not knowing your level of computer literacy I'll just start with this: have you rebooted your computer lately?
If a simple reboot of your Mac doesn’t fix things, see if the problem still happens in safe mode.
How to use safe mode on your Mac - Apple SupportÂ
Safe mode will often correct weird software behavior by forcing the OS to do disk repair, clear caches and other housekeeping and temporarily disables third-party mods. When you're in safe boot, the machine won’t be at its best performance, especially with graphics, but that's expected.
Does the same thing happen while in Safe mode?
You can exit safe mode by restarting your Mac normally, then reevaluate the problem.