Capital cousin misguidedly invested in decentralised altcoin (8)
I believe the answer is:
asuncion
'capital' is the definition.
(Asuncion is an example)
'cousin misguidedly invested in decentralised altcoin' is the wordplay.
'misguidedly' indicates anagramming the letters.
'invested in' is an insertion indicator.
'decentralised' means to remove the middle letters (the centre of the word is removed).
'altcoin' with its centre taken out is 'an'.
'cousin' anagrammed gives 'suncio'.
'suncio' put into 'an' is 'ASUNCION'.
(Other definitions for asuncion that I've seen before include "Capital of Paraquay" , "Capital city of Paraguay" , "South American capital city" .)