If you are looking for breakfast or lunch - try looking for single reservations with close times. That is how we managed to eat PPO every day that we wanted to when we scheduled a trip less than 60 days out. We also got a couple of lunches that way. For dinner - I suggest looking at all party sizes. We were 3, but got a reservation for dinner for 6 and then reduced the size of the party. Good luck.
Keep trying as a reservation may open.
As mentioned in other threads, try the touringplans reservation finder. This has worked well for us in the past. It used to be free, now it looks like you may need a subscription to use it (IMHO, it is worth it).
We also enjoyed Skippers Cantina and it is often easier to get a reservation.
I didn't see anything 60+ days out, but about 3 weeks before our arrival a number of lunch and breakfast BOG ADRs opened up [I just took all that were opened and then decided which of them to keep, and cancelled the rest so others could use them -- kept one breakfast & one lunch ADR]. If you have MDE app, that is a faster and more effective way to snag them.