I think a trailer for Wakanda Forever could be released online before their panel at SDCC, since it's possible the trailer will be attached to Love and Thunder.
After 3 years and almost everything announced in that panel being already released. I doubt their panel would be just about one movie.
Ant-Man 3, Guardians and The Marvels already finished shooting, right? Maybe new footage? Or maybe just more info (due we know anything about The Marvels despite knowing who the three leads are?).
Blade and Captain America 4 are possibilities as well. A director announcement for FF? A cast announcement maybe, which would be huge enough. There's also Deadpool 3, Thunderbolts and that Scarlet Johanson project.
For the shows, DareDevil, Echo, Armor Wars, Ironheart, WonderMan and House of Harkness could all get release dates.