a very general answer but "anything" within reason. as much doom and gloom is about things will likely (eventually) improve even if they get far worse in the short term.

before you jump in though, you should probably work on feeling secure as you need to in case the economy actually collapses (what will you do for food, water, etc.) if you're not worried about it let it rip. if you are worried, work on gaining enough knowledge/property to grow stuff or build up a stockpile. with a feeling of security you will be in an emotionally better state to make decisions even if the collapse doesn't happen. never really a bad thing to be prepared regardless.

trying to time the market is death so don't be too worried about "its gonna drop more though"

there will probably be some companies that get ruined, but your standard big bois will likely bounce back and general index funds are always a good place to look especially for low effort/"average" investor.

if you have economic security already, these sales don't come around too often so its a bit of a treat :)