I'm looking for a good database provider for a project where I'm working with knowledge graphs. I've checked out Neo4j as a possibility but are there any others
Did you try FalkorDB? If latency is a factor and you consider to store many Knowledge Graphs you should check it out.
DozerDB: extends Neo4j Community with features such as multi-db. https://dozerdb.org
Memgraph: https://memgraph.com/memgraph-for-neo4j-developers
Apache AGE https://age.apache.org/
And much more….