Remove the add-on anti-malware.
Some of that add-on anti-malware has had a history of privacy issues, too. For instance, Avast was selling your entire online and purchasing activities. They claim to no longer being doing that, of course.
Add-on first-few-hops VPN apps can also cause issues, and can (usually do) leak private info. Remove those.
Most interesting cases I’ve encountered involve the built-in anti-malware blocking add-on anti-malware from corrupting macOS due to false positives. We get the occasional posting about that around here, too.
Torrents are good sources of malware, and the cracked apps available there are increasingly used for distributing malware, and torrents in general can cause unexpectedly massive system and network loading.
Off all the add-on security apps, I’d suspect it’s that RadioSilence app that’s causing the issue here, and all (four?) of the VPN apps are always suspect when routing issues can be in play. I’d still also remove the two (three? Virus Barrier?) add-on anti-malware apps, and whatever other security apps I’ve missed, though.
Given how many security add-ons and torrent bits and VPNs and the rest I’m seeing loaded here, I’d probably wipe this Mac and start over
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PS: Printer vendors just fill a computer with… stuff, too. When replacing, consider getting printers with AirPrint support.
PPS: If performance becomes a factor, and given iMac 27” memory user upgradable, consider adding more memory. Not a big win given the SSD, but you’re using ~all of the existing 16 GB.
