You can try "Files and Process" payload of policies.

I would probably make an extension attribute and use the builtin "find" command to test for the presence of that file and then any other tests you would want to do.
find Man Page - macOS - SS64.com
Have you tried an EA?
#!/bin/sh
if [ -f /path/to/file ]
then
echo "<result>Exists</result>"
else
echo "<result>DoesNotExist</result>"
fi
@bravestface ditto what @donmontalvo is saying, then create a smart group based on the criteria derived from the extension attribute.
I used the following with a Smart Group. If you're in higher ed, it's probably student machines.
#!/bin/bash
LicenseFilePath="/Applications/VirtualBox.app/Contents/MacOS/ExtensionPacks/Oracle_VM_VirtualBox_ Extension_Pack/ExtPack-license.html"
if [[ -e "${LicenseFilePath}" ]]; then
EA_RESULT="Installed"
else
EA_RESULT="Not installed"
fi
echo "<result>${EA_RESULT}</result>"
I used the following with a Smart Group. If you're in higher ed, it's probably student machines.
#!/bin/bash
LicenseFilePath="/Applications/VirtualBox.app/Contents/MacOS/ExtensionPacks/Oracle_VM_VirtualBox_ Extension_Pack/ExtPack-license.html"
if [[ -e "${LicenseFilePath}" ]]; then
EA_RESULT="Installed"
else
EA_RESULT="Not installed"
fi
echo "<result>${EA_RESULT}</result>"
Thank you for all the great ideas. I'll reach back out if I have additional questions!
-D
You can try "Files and Process" payload of policies.

I want to make a Smart Group based on if a file is found on a device, but how do I use a policy that searches all computers for a file to do that? It seems the only results produced are in the Log -> details of the policy.
Have you tried an EA?
#!/bin/sh
if [ -f /path/to/file ]
then
echo "<result>Exists</result>"
else
echo "<result>DoesNotExist</result>"
fi
I have tried this script to find if Install macOS Monterey.app is in the Applications folder, but for the life of me I can't get it to work. I have tried " and \\ but nothing.
I tried it using a testfile.rtf placed in applications and that worked fine. Why won't it work with a macOS installer .app file?