Raft does do persistence and crash recovery, at least of the transaction logs.

What you need from your side (and there are libraries that already do this): a) A mechanism to snapshot all the data b) An easy in-memory mechanism to create indexes on fields--not strictly needed, but definitely makes things a lot more easier to work with.

Bespoke data structures are just simple classes, so if you're familiar with traversing simple objects in the language of your choice, you're all set. You might be over-estimating the benefits of a query engine (and I have worked at multiple places that used MySQL extensively, and used MySQL to build heavily scaled software in the past).

>persistence to disk, WAL, crash recovery, indexing, vacuuming (you're using tombstones for your deletes, right?),

The point of Raft is that you write your service like it was a single instance, using SQLLite or non relational equivalent, and then use Raft to run a distributed system that can have redundancy, all without additional infra involved, and for the vast majority of the use cases (i.e some backend or some web app service at a startup), this is more than enough, considering there is enough low level stuff in drivers and kernels to make data reliability pretty high already.