While maxing out tax deferred accounts is great (saves you on taxes now and potentially better compounding), keep in mind that you're essentially locking the money up until 59.5. If your income allows you to contribute to a ROTH, you absolutely want to do that for as long as possible.
If FIRE is a major goal (and the RE part is before you're 60), then I'd suggest that you also invest a significant amount of your disposable income into a traditional brokerage account. When you RE, you're going to need income from somewhere so building up a big enough post-tax pile that throws off income (by way of returns and dividends) is a sound strategy. I personally have a 50/50 split between tax deferred investments (401k SEP, HSA) and post-tax investments.
I use the same mix of stocks, etfs, REITs, and mutual funds in the SEP and post-tax account. Is this the 100% most tax efficient way to go? No. But my purpose for investing is to:
1. Meet my short and long term goals within my desired timeframes
2. Be as tax efficient as possible while doing so.
Hope this helps.