If you are planning a specific destination, cabin & aircraft, it really is not worth thinking much about this until 30-45 days prior to departure. Everything from schedule to arrival & transit requirements may change. Fully agree that if the goal is an F trip, watch availability and grab what comes up. Even then, do understand that the chances of anything booked in advance sticking without a lot of flexibility on your part is fairly remote.

If this is once in a lifetime and you feel up to it, I would wait for 2022.