What’s the proper method to mount network racks to a commercial steel stud wall?

I’ve been getting mixed answers, some say to use snap toggles into the studs and others say sheet metal screws will work just fine. We will be mounting two 10U hinged IDF racks with plywood backing (fire-rated).

What method has worked well for you? I’d appreciate any feedback/suggestions. Here’s an example of a hinged 12U IDF mounted to a wall with plywood backing. Can anyone tell what the installer did here?

Ideally, I’d like the two racks to hold a UPS, switch, and a patch panel.

Thank you.