Don't all verbs use have as the auxiliary in the present perfect tense? As such I am enthused would not be an intransitive verb, but either a nominal predicate

Don't all verbs use have as the auxiliary in the present perfect tense? As such I am enthused would not be an intransitive verb, but either a nominal predicate or a passive verbal predicate. A correct intransitive form would be "I've enthused about going to Disneyland". In the first case enthused should be replaced by enthusiastic, which is the correct adjective, in the second case you would use by rather than about as a preposition for the agent. Correct?