Here are the steps to change the OS to Sierra on your mini if you decide you want to try it:
Backup your system to an external drive in case you need to go back to 10.13. I use
Carbon Copy Cloner, it is faster and much more reliable than Time Machine.
Download Sierra from the App store, it does not appear when you search for it so use this link:
http://appstore.com/mac/macossierraAfter the download finishes, it will launch but you will get a message stating it can’t install, simply close it.
Insert a USB flash drive, at least 8gb in size, that has nothing you need to keep. Rename the USB drive “SierraBootInstall”.
Open terminal, copy/paste the following command and hit enter:
sudo /Applications/Install\ macOS\ Sierra.app/Contents/Resources/createinstallmedia --volume /Volumes/SierraBootInstall --applicationpath /Applications/Install\ macOS\ Sierra.app --nointeraction &&say Done
Enter the admin password if requested and hit enter. It can take up to 30 minutes to complete depending on the speed of the USB drive. You will see “Done” when it is finished.
Reboot the Mac and hold down the Option key. Choose “Install macOS Sierra” from the boot menu options.
Before you start the install, run Disk Utility from the menu and erase the Mac’s hard drive so you will have a clean install of Sierra. Exit Disk Utility when it is finished and run the Sierra installer.