It is not a published benefit to get a complementary suite upgrade confirmed in advance, even within 24 hours. If you want the suite confirmed before you check in, use a suite upgrade award.
Yup!
Spending 90+ nights per year at Hyatt branded properties worldwide I can tell you for a fact you are better off just simply picking up the phone and calling the property and honestly explaining yourself. If your profile looks strong it's a good chance they will act proactively. If you are a Glob-lite, probably not, but
maybe.
PS-not uncommon to book a base room on cash or points and call the hotel and ask to pay a supplement to get a different upgraded room type. Winds up being discounted from a full cash rate, sometime significantly. I'll generally employ this technique at Andaz, Alila and SLH properties.
If I "must" have a specific room type and will otherwise feel unhappy if I don't get it, I book it upfront. Few extra buck and no stress and I know I will get what I want (or better).
Just that simple