with minimal need to prep for software architecture patterns and related topics: concurrency, distributed storage, networks, OOP, OS, web infrastructure
This depends on the definition of the role from company. Data scientist can mean very different things at different companies. Usually MLE will get these system design questions
You’re confused
The options are even more confusing
I already did a survey on Glassdoor and have collected moderately sufficient stats. But it's good to cross-validate against another source. DM if you want the figures. I don't want to publish here yet to avoid anchoring the poll results with psychological bias.