I've been traveling using Marriott for years. The best way to get the suite upgrade using your suite upgrades (not via bonvoy level), is AFTER booking. Put in the request for the suite upgrade and then call. Im using points for the Swan Reserve. I was hoping to get an upgrade based on my level, but I doubt it. Sometimes they send out a last second upgrade to a suite for a discount email. I'm watching for that too.
On thing that you can do, that starts to sound crazy, but it's pretty easy - is using the marriott website to book (not the app). And rather than using all the points on the room, upgrade the room to the suite you want so it's secure, and then pay with a points & cash combo. That feature is not on the app. That is one way to MAKE SURE you have exactly what you want at an awesome discount.
Last thing is, I don't think you need all your points in place to book. You'll need them by the deadline on the ressie, which is stated when you book. Don't hold me to that b/c they keep changing things. And it may not be available to new accounts, but I'd try.
If you make a habit of using the card for everything, you'll also accumulate free nights over the year as part of the spending comps on the card.
I've never stayed at the Swan Reserve before. Hoping it's nice and comfy.
Best of luck to you with booking.