I have a Roth IRA that I max out every year and a brokerage account that I put other money in. I'm a 1099 worker with 0 benefits so there's no 401k option with the company. I've heard about Solo 401k but I don't really understand it. **Is Roth IRA+Brokerage the best I can do** or can I optimize tax by doing other things like a 401k? Or is it not possible to have a 401k without the company?