Another article making blanket statements without explaination .... 🙁

Multiple filegroups - maybe. Not always. Two reasons.

Split for performance - requires that the DB is IO bound to have any effect and that the filegroups are split onto multiple separate IO paths. Multiple files on the same drive will have no effect. Requires some careful analysis of which tables and indexes get the heaviest IO load.

Split for recoverability - for when the DB is large enough that it can't be restored in the time allowed by the RTO. Split the DB so that the critical part can be restored fast and the rest later. Requires Enterprise edition and careful analysis of what tables are needs by what parts of the app, what's critical and what's not.