I feel you, and nor were those prices reflected at the time of signing the contract (which shows 2020 pricing) or on the current Amenity Price List (2023 pricing) on the jetstream website. It is a crappy situation, but given that it's use-it-or-lose-it, I'd say maybe give someone status (or upgrade yourself) with your remaining amenity funds, buy the wifi subscription, or gift someone in the family E+ subscription. Those are the only options that are "worth" it imo. Of course, if you've already invested and don't have these options, then it becomes a something-or-nothing situation so might as well get the award flight.

I'd be hard pressed to make any investment in the 15-40K range with the new award chart given the opportunity cost of spreading those expenses throughout the year. 45K could perhaps turn into a gift of 1K status to a non-FF spouse/kids for the plus points (which you can hopefully use up in the year). Then there's GS benefits beyond that at 75K. 10K and 15K gives you just about enough amenity funds for Silver -> Gold or Gold -> Plat, UC membership, Wifi subscription, so you're getting good value still.