Graph DB recommendations

Any recommendations for open source graph db? Typical data will have around 25M nodes; as per current understanding the data will be similar to any social graph or supply chain management. In future we possibly want to try GNN based model.
The deployment will be on-prem or bare metal. Neo4j is not an option due to cost implication. The free version of Tigergraph supports up to 50G - not sure if that is good enough for our data.

datascience graph recommendations