Etrecheck shows a Major Issues

Unsigned files - There are unsigned software files installed that could be malicious and should be reviewed.

That usually indicates older software is installed. That commonly happens with one uses Migration Assistant in setting up a newer Mac from an old one. MA does not always eliminate older items.

It could also be software from other than the Mac App store. Apple's info on signing is here:

Intro to app security for macOS - Apple Support

I saw an entry for a Brother support file that shows an install date of 2016, long before the M-series Mac Minis were introduced. It could be something as simple as that. If that it is all it is, it should not present a danger. You can check if a newer software version for your Brother device is available. If you no longer have a Brother device, There should be an uninstall function in a Broterh support folder.

Did you encounter other issues that caused you to run EtreCheck? If so, please let us know.

I see a few minor concerns, mostly that your storage performance is slower than I expect in most M-series Macs. That could be due to using three Cloud backup systems, or using a client-side VPN (NordVPN). Most users have no need for a client side VPN unless your employer issues you one. Interesting white paper reviewing the need for and security of various client-side VPNs on the market:

https://innovation.consumerreports.org/wp-content/uploads/2021/12/VPN-White-Paper.pdf

Those that advertise most heavily seem to not fall in the "favored" category.

Review how much you are uploading to Google Drive, OneDrive, and Dropbox. Massive backups are not good. I only upload current project files to Dropbox when I need to access them from my laptop or iPad while traveling.

Delete these files & restart...

/Library/LaunchAgents/com.logmein.hamachimb.plist

/Library/LaunchAgents/com.microsoft.SyncReporter.plist

/Library/LaunchDaemons/com.teamviewer.teamviewer_service.plist

/Library/LaunchAgents/com.teamviewer.teamviewer_desktop.plist

/Library/LaunchDaemons/com.aruba.hidswitch.plist

/Library/LaunchAgents/com.teamviewer.teamviewer.plist

/Library/LaunchAgents/com.microsoft.OneDriveStandaloneUpdater.plist

~/Library/LaunchAgents/com.adobe.ARM.***.plist

~/Library/LaunchAgents/com.apple.SafariBookmarksSyncer.plist

~/Library/LaunchAgents/com.adobe.ARM.***.plist

~/Library/LaunchAgents/org.virtualbox.vboxwebsrv.plist

~/Library/LaunchAgents/com.adobe.ARM.***.plist

~ tilde indicates your home folder

Apple hid the Users' Library folders...

Method 1:

1 From the Finder, select the Go menu at top of the screen, and choose Go to Folder.

2 In the window that opens, enter ~/Library, and click Go.

Or…

Use the Command-Shift-.