Very reasonable, but agree with the other poster that you will not always get a suite, even if there is availability.

TBH, I have no faith* in Marriott properties providing consistent upgrades anymore unless you book through a travel agent / Virtuoso, reach out to the property beforehand, or ask the front desk like you did.

Note: I may be slightly biased, as I moved 90% of my future stays away from Marriott after a few bad experiences earlier in the year.