I think 6 months in cash is probably suboptimal for a lot (most?) people. We have cash sort of on accident right now, but generally don't carry cash for the reasons laid out here:
https://earlyretirementnow.com/2016/05/05/emergency-fund/
I would add to that if you're a typical employee, you probably have access to a 401k and Roth Ira each year, so that's up to $25,500 you can put in tax deferred savings each year. I certainly wouldn't forego maxing that out in order to have cash handy. Contributions to a Roth IRA can be withdrawn tax free, so that can acts as an emergency fund in a pinch, even if it can be painful to take it out of stocks in a downturn. You will have some risk early on, but if you get started early enough, you should be able to manage that risk until you have decent money saved up in a roth. The biggest issue is not running up commitments (house note primarily but lifestyle in general) that makes a downturn unduly risky to you. Probably most importantly, if you have a two earner household, you cannot afford to live up to your income the way a single earner household might, because even though it's less risky in the sense that you will likely have at least one income coming in, you actually double your risk of having a job loss, and being able to meet 50% of your obligations is only slightly less catastrophic than being able to meet 0% of them.