You are very optimistic.

My guess, only a guess, is that we are at the lightest HK requirements. It won't be eased further in the foreseeable future. With strict pre-departure and arrival tests, plus expensive and strict 7-day hotel quarantine, the past traffic to HK is severely limited. That is tourists, MICE events and even business. Transit is very limited by the few flights offered by CX. And there is always the risk of flight suspensions. Finally, the health requirements on crews limit the number of flights that CX can offer.

I don't see CX using more than 2 slots in the coming year(s). It would not be sustainable to use 80% just to keep them. Whether they sell or rent them (if feasible) is another question.