There's a real difference, and it's mostly in who signs and what's bundled. Corporate housing means a fully furnished, move-in-ready unit rented to a business client or someone traveling for work, usually for a month up to several months. The package includes furniture, utilities, internet, kitchen goods, linens, and often cleaning. The tenant walks in with a suitcase and starts work the next day.
A furnished rental is the broader term. Any furnished unit is a furnished rental. It becomes corporate housing when the clientele is business driven and often when the company, rather than the person living there, is the one paying and signing. That payer matters more than it sounds. A company paying from an accounts payable department behaves differently from an individual paying out of a paycheck.
So on your 900 unfurnished 3 bed, the furnished corporate version rents for meaningfully more, because you're now covering electricity, water, internet, and replacing a mattress every few years. Some of that premium is really you being reimbursed for expenses you took on.
The thing that catches people in a market like yours is that demand is lumpy. Traveling nurses and line crews show up when there's a contract or a storm. Your occupancy depends on a small number of employers, and if the hospital changes its staffing agency, you can lose your only source of tenants. Before you furnish anything, find out who those employers actually are and how they place people.