In fun, absolute ruler's beginning to splash out — he can certainly afford it! (6,2,6)

I think it could be either:

Which length description are you looking for?:

6,2,6

sultan of brunei

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'beginning to splash out he can certainly afford it' is the definition.
I know nothing about this answer so I can't judge whether this works.

'in fun absolute ruler's' is the wordplay.
I cannot quite understand how this works, but
'ruler' could be 'sultan' (sultan is a kind of ruler) and 'sultan' is present in the answer.
This explanation may well be incorrect...

Can you help me to learn more?

I've seen this clue in The Guardian.

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