Here’s my poorly thought out plan for when we overthrow the monarchy:
Similar to Jury Service, someone gets randomly summoned to be head of state of the United Kingdom for a set period of time, say 10 years.
For the duration they get to live in a palace, wear crowns and cut some ribbons.
When their time is up they can return to the anonymity from whence they came. Or alternatively use the gig to launch their social media career.
Go on, improve on this: