If you have a business, or can fake it a way acceptable to AmEx, and your timeframe is a year or 2 or more, you could probably add several AmEx MR business cards (and SUBs), including multiple accounts of the exact same card, to the path:
(1) get an attractive SUB offer on the "vanilla" platinum and use it for one year,
(1.5 or 3.5 or 4.5) open a Business Plat or 2 or 3 and/or Business Gold or 2 or 3
(2) open a CS Platinum for another SUB,
(3) close the "vanilla" platinum,
(1.5 or 3.5 or 4.5) open a Business Plat or 2 or 3 and/or Business Gold or 2 or 3
(4) use the CS Platinum for another year, and
(1.5 or 3.5 or 4.5) open a Business Plat or 2 or 3 and/or Business Gold or 2 or 3
(5) cash out/close out (with 3-4X or more the 250k estimate above) completely after the year on the CS Platinum.

Might also be able to add a personal Gold to this path.