ERPNext is the actually open source accounting software to consider here.
Interesting choice of a TLD. At first I thought it was free (like eu.org) but it seems that it's around $15, so pretty much like other domains. Is there a particular reason you went with .us.org?
What kind of manufacturing do you plan to support? And what does it mean to be specific about support for American manufacturing?
Github link on https://erpnext.com/ goes to https://github.com/erpnext which is pointless.
Actual repo seems to be https://github.com/frappe/erpnext and is GPL-3.0.
I run a manually installed, locally hosted instance. It's not much of a hassle.