You should also checkout ERPNext (https://github.com/frappe/erpnext). Its another free and open source ERP (GNU GPL v3) which is not open core. ERPNext is also built as a monolith, so you get maximum features out of the box instead of relying on 100s of extensions to fulfill your requirements. All since there is no "enterprise" version, there is no chance of features dropping out like accounting and payroll.

ERPNext has reasonable traction too (~5k+ stars on GitHub, 12k+ forum members) and is used by some very large enterprises.

Disclaimer: I am the founder of ERPNext