is it possible to permanently unlock the wallet?
This would be not having it encrypted in the first place.
I am on a really shit PC and keeping the wallet open for more than 12 hours is out of the question for me
So every time I restart the wallet the next day i would find it locked again, does that mean i would not be able to properly stake ever?
No, just leave it open as much as you reasonably can. You may just take longer, but the older your stakeable coins are the more weight you will have so it will work out OK.