Racing fpv goggles require very low transmission delays else the actual position seen on the goggles could be misleading and could result into mishaps. If you are going in for a racing drone and fpv, check the specifications carefully.
Usually racing fpvs are expensive.
Swelling on the lipo batteries is usually seen when their internal electrolyte breaks down due to over heat or excessive current flow. Batteries in such conditions should never be used again as they might catch fire or explode.
I use cheap $40 cases. They protect well and I can replace them after two years if need arises but they are still ok.
Only negative is that they are not hard shell and should be carried as hand baggage if travelling by air.
I don’t see any point in spending huge money on them if they protect...
The DJI props are self tightening type props and get tightened during flights. However you should tighten them enough by a finger that they don’t come off during initial breaking. It’s known that if the props are lose and you apply heavy breaks, there are chances to get them further loosened.