So kind of surprised that no one posted about this on here but i'm guessing most people don't play the pve version of fortnite. But currently at least until they come in and patch it. The fight the storm 4 player when failed gives pretty decent rewards because normally it's split between the 4 people who would be participating.
1. Grab 3 blue glow
2. Find the defense spot.
3. put blue glow in turn it on and let it get destroyed 3 times
4. fail the mission and get free experience drops of rain and rewards which are worth your time.
Example lvl 70 missions usually give 20 drop of rain 5k exp of sources depending on the rewards. Some of the lvl 90 missions over 10k exp and obsidian or / shadow crystals.
I'd imagine this will be fixed soon because people have been talking about it a lot.