I think your Pi was a victim of moisture because of that case it was in. I hope it revives.
I use various sizes of these "waterproof" enclosures from chinese sellers on ebay. I'd buy local but the price is 4 times the ebay cost. Several have been outside for over a year.
This one is good for a Zero with some accessories and a cam. This particular Pi doesn't have a USB flash drive and the CPU is typically reporting -8C less than the same configuration but with a USB flash drive for storage. So a USB flash drive adds quite a bit of warmth to an enclosure.
This one is good for a Pi 3 size Pi with accessories and a cam.