Stake means you mean we can mine eth without the hardware .......? just from desktop if we deposit some amount of eth for stake.....?
Yes. But of course, if you don't have that much ETH, don't expect to "mine" anything significant. More ETH that you stake, the more ETH you gain. Pretty much like how you gain more bitcoin the more mining hashrate you have.
ETH doesn't have a total supply cap as far as I know. So yes, it will keep on inflating.