Qs about types of accounts from the course

In his recap (Putting It Together Video 1: Layers and Checklist) we’re looking at a list of all the types of accounts described earlier.
As he says, they are all optimizations on the basic idea of a brokerage account.
To make sure I understand though - all those accounts require an employer. Most (all?) of those account types have requirements as to the type of income you are investing, when it was taxed, or employer matching, or other things.
What if you don’t have traditional employment? If you are self -employed yout still might have 1099s I guess.
But what if you came into a lump sum windfall? or an inheritance that you want to put to work.
I believe a plain brokerage account is your only option?