I have numerous devices that send alerts via email (UPS, KVM, alarms, etc.). What tool do you use to aggregate these alerts? Perhaps in a dashboard? Thanks!

I've used zabbix and PRTG- both were great.

Kuma

Don’t aggregate mail. Use a monitoring tool like prtg, zabbix, etc

Send all the alerts to Teams, Slack, or Zulip Channels?

Free zullip chat with email Integration works great. Make chat channels and have your devices email to them. Nice mobile app that alerts you of inkomming mail alerts. You can even mute specific channels when they are too noisy. https://zulip.com/integrations/email

Zabbix and PagerDuty

We've been using PRTG forever, we're just a lil nonprofit, and the pricing and sensor limits on our plan is killing us. I deployed an Ubuntu box with Zabbix and holy hell was it easy to set up. Learning to USE the thing is a steep learning curve but it's incredibly robust for a free open source monitoring solution.

Some older devices only send mails

They both require an agent. What if i only need to monitor a remote UPS?

It’s hard to keep track of whats actually down/at fault

Why not just have it set to email your helpdesk?

Then a ticket is created for you automatically and also allows you to track consistent problems reported

PagerDuty / AlertOps seem to be the only products suitable for my situation. You create a “service,” and they generate a unique email address to which notifications are sent. But I was looking for something more affordable or open source.