I found some info on the Apple Developer’s forum, and here’s what I discovered and had to do to make it work:
On iOS/iPadOS 14.2, no “Profiles & Device Management” option is available under “Settings > General” until there is a profile installed. For whatever reason, the Prey certificate is not able to properly trigger the option to install. What I discovered was…
I had to first install the “iOS & iPadOS Beta Software Profile” from Apple here:
Once I’d installed the beta profile and restarted, the “Profiles & Device Management” option became available under “Settings > General” — and when I downloaded the certificate from the preypanel website, it properly triggered the installation.
My guess is that for people with a profile already installed, this isn’t an issue—but for those, like me, who don’t have one and are experiencing difficulties, try the above and let me know! I was incredibly frustrated and couldn’t find anything on the web about it. I did it first on my iPhone and it worked perfectly. Thinking maybe it was a coincidence, I tried on my iPad a few times before installing the Apple profile—but again, it wouldn’t install until after I’d installed the Apple Beta profile, after which it worked perfectly.
Hope this is helpful to someone!