I think
@Arcades makes good points about the Biz Plat. I'll add some more. It's even better if you open one, refer P2 to an Amex card of your choice (I got a $0 AF biz card for P2) using the current support offer of 15K MR plus 4xMR on all spending up to $25K spend (exp. 12/1/21). That way, you'll be stacking MRs on top of your SUB. And there's also a
current offer to add employee cards (green ones are free) and get 20K MR for $4K spend per employee card up to 100K MR total. If you have five employee cards to max out that offer, you could rake in MRs.
In my case I got a 150K MR/$15K MSR SUB targeted offer. P2 got an Amex card using my link, so that I could get the additional 4xMR. P2 has an employee card from my Biz Plat. So on that employee card, I'm getting 20xMR per dollar on the first $4K spend: 10x from SUB + 1x regular earning + 4x supportal + 5x employee card.
You get automatic Marriott Gold and Hilton Gold by holding the Biz Plat (just make sure to enroll).
You could pick Southwest as the airline for the $200 airline credit. When you use MRs to book flights with the Biz Plat, then you would get 35% points rebate on your chosen airline. Additionally, First or Business class fares on
any airline also qualify for the 35% points rebate.
If you'd rather have the SW CP, then the new offers look great too.