Nill

An easy & free option would be Discord as it can accept Slack webhook notifications. Either use an existing channel you have control over, or add a new dummy server, and create a new webhook in the channel's settings. Take that webhook url and simply add /slack to the end when copying the address into the Slack Agent configuration in unraid. If you run multiple servers you can create different webhooks for each and give those individual Discord icons for easy identification.

The flexibility given by the wide variety of plug-ins and apps to greatly extend the function and features of a "file server" is what's bringing me back to Unraid after trying other storage solutions. More granular encryption options; file/folder/share encryption decrypted on network user authentication instead of whole drive w/passphrase on boot.