A state may have a monarch without that monarch running its government. In a constitutional arrangement, the office can represent continuity while ministers and legislatures make political decisions. In other monarchies, the ruler holds substantial executive authority. The title alone does not tell us who governs.
In Britain, constitutional arrangements separate the enduring royal office from day-to-day party government. Understanding the monarchy therefore requires looking beyond the monarch to the ministers and institutions that exercise political authority.
Continuity brings a succession problem
An office that is not regularly contested can offer a recognizable focus for ceremonial life. Hereditary succession can also make the next holder predictable, reducing one kind of uncertainty. Yet predictability does not ensure competence or consent, and family disputes can make succession uncertain again.
Where a monarch governs directly, much depends on the judgment of the person holding the office and on the institutions capable of constraining them. Where the role is constitutional, informal influence and the boundaries of ceremonial authority still matter.
To understand a monarchy, follow its actual decisions: who appoints officials, controls public resources, interprets the rules, and can challenge the ruler. The same crown can sit above very different distributions of power.