I don't think anyone is reliable right now. The best idea might be to look at which single day tickets are sold out, the pricing calendar for single day tickets, and if Keys are blocked. For our early June trip, I know June 1st and 2nd are already sold out both for single day tickets and reservations, as is May 31st. These are the last two days of the lower tier Keys before the summer blockout happens. So I'm anticipating those days are going to be tough after the early morning. Funny enough there's still Key availability on those two days so they've cut off the general public and left room for passholders on those final two days. That's actually a cool thing for them to do since there will be plenty of final moment demand for those Key holders with Fantasmic coming back. I actually agree with Touringplans on those days because it makes a lot of sense with the finality of the passholder availability for a while.
June 3rd and 4th, only the upper 2 tier Keys can be there so it will be probably lighter days combined with higher single day rates. No issues with availability for reservations or tickets those days. I don't think it will be 4s and 5s but it shouldn't be as busy as May 31-June 2.
Who really knows at this point? There's so much revenge travel that's about to happen that I don't think we'll see those easy DLR days again until next year.
A good idea is to rope drop, have a plan, and try to get as much done before the afternoon crowds show up.