Unless this has changed recently
If you book room only, you are guaranteed the rate you get on the phone - which is the current year rate for dates, not the highest holiday rack rate of current year. I booked our room for April/May 2021 and got it for the same rate as the same dates for 2020.
Same thing happened last year - booked room only, got locked in at current years rates which were not the highest rack rates of year.
The only way your rate will change is if you change to a package, change dates or change hotels - updated that now you can book a "basic package" for 2021 and pay $200 deposit.
I know people get conflicting answers on this, so I always try to give our experience when I see these kinds of questions!