We only need to go back a couple of years to mid 2020 when every company was laying people off. Layoffs.fyi was tracking multiple new rounds every day. I fear what is coming is going to be that or worse.
- hoard cash, i.e. don't spend it on things you don't need right now, you might need it a lot more in 6-12 months just to pay the mortgage
-do anything and everything you can to have a nest egg that will give you 18-24 months of living expenses; 6 months won't be enough for a lot of people. Not easy for everyone I know, but if the SRHTF, it might take you that long to find a new job - and that new job might not pay as well as your old one.
-get out of debt if you can. Again, not easy, but owning a house and car free-and-clear is an awesome feeling when the economy goes into a bad recession and you don't risk losing your house as long as you can pay taxes and insurance.
-get a side-gig or two on top of your job if you can, having a few irons in the fire is never a bad idea if you can handle the extra work.
-not a good time to switch jobs to a risky small tech company (or even a big tech company) if they never, or rarely make money - sooner or later VC's will stop writing checks to companies that don't have a prospect of becoming profitable - in a severe downturn, VC's will cut their losses and move on; these types of companies will be hit the hardest.
-if you are working at mega-corp, try to get on - or stay on a team that supports or develops projects that are really important to the core company functions and/or makes them money. Not a good time to be part of a 'special group' exploring some new technology pr product that might not ever pan out - when big corps tighten belts, look for those types of projects to get shut down.
Have enough cash to keep you afloat for at least 6+ months of unemployment.
If that's not currently the situation try to cut back expenses where you can to reach that state (to a reason), and imo even on the expense of 401k contributions (but please remember to start again once you have enough cash).