policy control
It’s not exactly the same, but you could use puppet to enforce configuration
Software Center with software allow lists
You can setup a custom repository with only approved software and then set that as the only one that the system is configured to retrieve packages from. This can also be controlled via puppet.
controlled OS updates
Same as the previous point. Upgrades are installed from the repos.
zscaler
I don’t know what that is/does, and their website isn’t helping.
software detection tool to detect what’s been installed and determine if any unallowed software is present
I’m pretty sure carbon black app control has a linux version.
antivirus
There are a number of different antivirus solutions for linux. A quick search will give you a bunch of lists. I’m not personally familiar with any of the options, but I don’t imagine it will be difficult to find one that will work for your use case.
I watch a new anime and the op/ed is a banger