Is there a word or term or phrase (in any language) that describes a person who has a lot of grand ideas for their life but doesn't actually do any of them? Something like a daydreamer, or a dreamer, or an uninhibited person, or a free-spirit?
Mittyesque, based on the fictional character Walter Mitty, who daydreamed of being an adventurer or hero.
I believe what you’re searching for is the adjective Armchair.
Armchair [as modifier] Lacking or not involving practical or direct experience of a particular subject or activity.‘an armchair traveller’
Some common usages for this are ‘Armchair Adventurer’ and ‘Armchair Enthusiast’. Both to indicate interest in a subject/activity without actually having experience or doing the thing.