FI in 5?

38M/38F 3 rugrats
3.4M NW
Personal house: 1.5M owe 260@5.75%
Rentals: 1.46M owe ~700k@3.44-4.65%
Rental income ~ 4k month after all expenses
Cash HYSA 70k
W2 combined: 300k +
MCOL area

401k 567k ~ half Roth/traditional
Roth IRA 180k
Brokerage 280k - 230k of it in SGOV
180k in 529s, split across all 3, with a GI Bill (36 months college expenses, can split)

Retirement:
Estimated 4k monthly pension with cola adjustments (military) at 60
Low cost Tricare at 60 till Medicare
Maxing 401k and IRAs

Looking to spend around 200k a year in retirement. Would like to reach FI in 5 years, I’ll continue to max 401k and IRAs. Probably not full retire, but pull back my hours and say no a lot more. I would be making at least 200k during that time, till I full blow retire at 60 or earlier.

1. With excess investment, where should I be investing? Mega Back Door?
2. What is the best investment strategy going forward? I have a feeling I’m going to get destroyed by RMDs at 70, considering how much traditional 401k I’ll have. Good problem, but not tax efficient.
3. I was saving up money to purchase a lake house to airbnb, vacation and possibly future primary, but with interest rates skyrocketing, I’d like to start divesting my SGOV position into better investments. I have been DCA into VTI currently. Or do I just pay off the house, but lose out on write offs?