I don’t know if it’d be unethical to let her be outside. Could birds of prey get to her or other wild animals? That would be a disqualifier.
I like the Five Freedoms when considering ethical keeping of pets, they are as listed:
Freedom from hunger or thirst by ready access to fresh water and a diet to maintain full health and vigour
Freedom from discomfort by providing an appropriate environment including shelter and a comfortable resting area
Freedom from pain, injury or disease by prevention or rapid diagnosis and treatment
Freedom to express (most) normal behaviour by providing sufficient space, proper facilities and company of the animal’s own kind
Freedom from fear and distress by ensuring conditions and treatment which avoid mental suffering
If you could provide her with a house on the lanai (indoors a cardboard box with two exits is fine but for the outside, sth wooden would probably do better), a few tunnels, a dig-box and an elevated vantage point, I would consider letting her her out on the lanai. We are a house bunny forum so we normally advocate keeping buns indoors, but it is important to consider the animal’s own wishes. “Unhappiness” takes a toll on the immune defense f ex.