Ask HN: System Design Resources espcially for unusual system design?

I am looking for something to help with generic system design and building a base for questions especially outside of the usual system design that focuses on web apps.

I was once asked a system design question for designing a sports book betting model. I had to come up with a model that calculated odds for many games / parleys.

There was nothing about load balances, end users, APIs, or DB choices.

Every time I look online I see resources that seem to almost entirely focus on system design for full-stack web and mobile apps. Everything is about load balancers/APIs/latency/replicating data...nothing about how someone might design any other piece of software.

Any run into this and have recommendations?