Optimum os for late 2014 Mac mini?

VivaMuse wrote:

SSD drive, Memory: 16 GB, and  Processor Speed: 2.6 GHz. OS Big Sur now, wondering if I should go to OS Monterey?

From the link John posted…

To maintain your computer's security, stability, and compatibility, Apple recommends using the latest macOS that is compatible with your Mac. macOS updates and upgrades also include the latest features and built-in apps such as Safari.

I would. Read How to download and install macOS - Apple Support.

By default, this model was configured with 1 TB hard drive, but it also could be configured at the time of purchase with a 256 GB SSD or a 1 TB "Fusion Drive" (which combines a 1 TB hard drive and a 128 GB SSD), either one, for an additional US$200.

What is the Storage Configuration on this machine ?

Rotational and Fusion Drives are all going to hold the machine back from performing to ones' expectations ?

A SSD drive could achieve the Performances you are excepting ?