'opulently-made' is a compound of the adverb 'opulently' (from 'opulent') and the past participle 'made'. 'Opulent' originates from Latin, specifically the word 'opulentus', where 'ops/opi-' meant 'wealth' or 'resources'. 'Made' originates from Old English 'macian' (to make).

'opulent' passed into English via Medieval/Church Latin and Old French forms derived from Latin 'opulentus'; 'made' derives from Old English 'macian' -> Middle English 'maken' -> past participle 'made'. The compound sense ('made in an opulent way') is a straightforward combination of these elements in modern English.

Initially 'opulent' meant 'wealthy, rich' (from Latin), and 'made' meant 'constructed or produced'; together they evolved into the descriptive compound meaning 'constructed in a wealthy/lavish manner' now expressed by 'opulently-made'.