I would separate the labour question from the responsibility question.
If you need another pair of hands working beside you, a newer person can make sense, especially if you have the time and structure to train them properly.
But if the real goal is to take yourself out of the field and free up time for design, clients, pricing, scheduling and growing the business, then you probably need someone who can carry more responsibility without constant supervision. A beginner may be cheaper on paper, but if they still require you to check, correct and manage everything, they may not actually create the capacity you need.
The risk of an experienced person leaving is real, but I would manage that through clear standards, fair pay, defined client boundaries, documentation, and a role they can grow into. I would not make the business dependent on someone staying loyal because all the knowledge sits in their head.
For me, the decision would be: what level of judgement do I need this person to exercise when I am not there? That probably tells you whether you need a trainee, a strong second pair of hands, or a genuine field lead.
