I agree that staffing them is the main problem, but I think it would make sense to revive some variation of the Nightingale hospitals in some form. Not perhaps so focused on ventilation, but simply increasing the number of beds quickly might be a wise investment.
I said at the time that even though it turned out we barely used the Nightingales, it was still the right decision based on what we knew at the time. I think the same applies now.