So how do we eventually recover if millions and millions of otherwise healthy cells die off?
That’s what immune systems are for. The human immune system is truly miraculous and breathtaking in its complexity and adaptability.
Also, viruses that are less deadly are the smarter ones, I think, in terms of natural selection. It’s hard to propagate your species if you insist on rushing to kill off your host.
If enough healthy cells die, the whole organism dies.