ABE isn't free, sadly (and iirc you need a DUNS number). Two month trial, but then $2.99 per device. Jamf Now is at least free for the first 3 devices, then $2.00 per month per device after that.
Another idea is perhaps Mosyle Business, which gives you the first 30 devices for free [1].
Another idea is perhaps Mosyle Business, which gives you the first 30 devices for free [1].
[1] https://business.mosyle.com/pricing