Great educational project! I'm curious why you are using Raft and also 2PC unless you're sharding data and doing cross-shard transactions? Or is Raft only for cluster membership but 2PC is for replicating data? If that's the case it kind of seems like overkill but I'm not sure.

Few distributed filesystems/object stores seem to use Raft (or consensus at all) for replicating data because it's unnecessary overhead. Chain replication is one popular way for replicating data (which uses consensus to manage membership but the data path is outside of consensus).