I found less than half price deals with Hilton en route out to Australia in a few weeks.
Dubai Hilton Jumeirah beach , & Singapore’s Conrad offered great deals, especially for Executive floors, lounge access etc. The booking format also asked if you wished to list for an upgrade on arrival for about £20 with clear room options.
I agree, the site if very awkward, prices vary if you don’t have the right links or codes, but they are there.
I already have a Hilton Gold card (via KLM), & a Virgin Atlantic Gold card. FlyingClub have 4 miles per £ for Hilton, using their Amex card also, I earned a lot of miles with the bookings.
Very good deals.