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Project management is deciding what gets done, in what order, by whom, and noticing early when the answer has changed. Everything else — the charts, the ceremonies, the frameworks — exists to serve those four things.
The discipline is not the artefacts. A plan nobody reads is not management, and a team that knows what it is doing next is managed regardless of what tool produced that.
Scope, time and cost move together: fix two and the third follows. Most project trouble is an attempt to fix all three, usually by hoping.
Quality is sometimes drawn as a fourth. In practice it is the variable that absorbs the pressure when the other three are held, which is why it degrades quietly rather than being decided.
They need the decisions. They rarely need the ceremony.
Until dependencies matter or capacity is tight. Then it hides exactly what you need to see.
Planning against people's nominal availability rather than their real one.
Half an hour with your own data usually saves reading three of these. The guides will still be here afterwards.