Anthony,
This is my opinion, but I do not generally advise people to use a self directed IRA for Real Estate investments. People use them, but Real Estate is already tax-efficient as-is if you're not wholesaleing and the IRA will prevent you from using those funds until age 59 1/2, plus they can be expensive to administer since they are not common.
As for the 401(k), I typically advise to contribute up to what your company will match. The real question is, will your investments provide better returns than your company's match amount? Additionally consider the timing of your goals. "Hardship withdrawl" is not an easy election to make, so consider your retirement contributions as being stuck in the account until age 59 1/2.
A more realistic approach to reaching your goal may be to use the BRRRR method to incrementally build monthly cashflow and use equity from each home's renovations to refinance on an additional property, and repeat until you get up to your monthly cash flow goal.
Feel free to message with additional questions. I work with individuals on tax strategy and financial goal planning to come up with a plan that works for their situation.