[alephnerd]

An internship is fine for onboarding becuase you aren't paying a FT employee level salary or benefits, and expectations are your hire is still learning but has some aptitude or interest in becoming a domain expert.

On the other hand, hiring a mid-career SWE who spent much of their career in one domain who is transitioning to another is a significant risk without additional social proof such as referrals where someone actually vouches for their skills.