It's not my job to discourage you, nor do I care to. It's still very possible to hit FI early, but I don't see 5 years being realistic at all.
You've posted a lot of stuff, and I'm not going to respond to all of it, but your biggest misconceptions seem to be that the 4% safe withdrawal rate is safe indefinitely with no loss of principal. That's not the case. The 4% SWR has historically been shown to not run down to zero over the span of 30 years, which is the length of traditional retirement. Not if you retire at 38. Also, the market doesn't grow 6% every year, so that you never lose principal if you only withdraw 4%. Some years the market returns negative growth, which is another way your math assumptions are off since you'll be digging into principal really hard in the down years.
The part about you the benchmarks not applying to you because you plan to be FIRE is also wrong. If you're aiming at FIRE, you should have way more saved as a proportion of your income than people working towards a traditional retirement age, not less. We're not talking about absolute dollars needed to sustain your lifestyle but the proportion you save, which clearly can't have been 50% for very long. You have less saved than your annual income. That puts you too far away from even a traditional retirement age.
I'm not going to download a random file posted to the net, but I don't see in your big wall of text what income you're going to live on between when you retire and when you intend to start withdrawing from your retirement accounts. You assume it'll all have 20 years to grow, but where is income coming from in the mean time?
Yes, you're putting a lot away into retirement savings now, but haven't been for very long, and since you won't be able to keep shoveling money in over the next few decades, AND you need to start withdrawing some of it to live on, you won't have time on your side.
You're also seriously underestimating your expenses over the rest of your life, in particular medical costs as you get older. If you plan to be out of the workforce soon, you will have very little in SS to count on as most of your productive years won't be paying into the system.