Investments for 1099 RN employee?

Hi all, currently a 1099 RN looking for ways to invest. Ideally, I may come close to making >160k so want to know options outside of the Roth IRA if possible. I do have a Roth that I’ve contributed to every year that I’m able to. Also, if I were to obtain another W2 job, can I still contribute to a self directed 401k in additional to the retirement plan my potential employer would offer? I’ve always had both a W2 & a 1099 income source, but trying to make only a 1099 work if it’s possible (much