They do always try to push a certain UY on people, but if you know you want a UY that works well for your travel, you can stand firm. If you are buying a resort like RIV or AUL, which are in active sales, its almost always possible to get whatever UY you wanted.
Basically, come December, every UY will come with 2021 points and beyond. It is not based on calendar year, but the UY for that month. For example, if I buy in February of 2022, I would get 2022 UY points and beyond if I chose a Feb UY. However, all other UY's would still get 2021 points since we had not yet entered that months 2022 UY.
So, if you are looking at a June, Aug, or September UY, for example, you would get 2021 points for all of those until you get to the 1st of that month in 2022.