I think the next State of Play will be July 29th, not in August:
-Abandoned's app releases on a Thursday (PSN store gets updated on Tuesday, Thursday is the State of Play day)
-Seems there's a GT7 Beta coming and seems to end 31/07/2021
-GoT DC recent blog post mentioned 'We’ll have more to share about the story of Iki soon' and 'We can’t wait to share more about Iki Island with you soon!'
-Death Stranding DC blog post mentioned 'we’ll have more to share on that in the weeks to come'
-In the recent State of Play announcement blog post they mentioned: 'This showcase will not include updates on the next God of War, Horizon Forbidden West or the
next generation of PlayStation VR. Stay tuned throughout the summer though, as we’ll have more updates soon.'
-Sony Japan accidentally (I assume it wasn't a troll CM) leaking the Bluepoint acquisition when announcing the Housemarque acquisition, which means the announcement should be soon since the CMs already had the related image ready
So I think this event will be at the end of this month and will feature:
-GoWR gameplay trailer and release date
-Horizon 2 new trailer and release date
-GT7 new trailer and beta available after the event
-Sony announcing they acquired Bluebo... Bluepoint and that they are making Metal Gear Solid and that the Bluebox app is to view trailers of both the MGS movie and MGS remake
-GoT DC story trailer showcasing the new story, locations, weapons, enemies, etc
-DS DC story trailer showcasing the new expanded storylines, locations, enemies, etc
-Teaser of how the PSVR2 headset will look listing some of their features
-Announcement of Dragon's Dogma 2 or a Capcom AAA new IP
-CoD 2021 reveal
-The Last of Us 2 Director's Cut (remastered PS5 version that includes the TLOU1 remake as extra content)
-EVO trailer teasing that Sony will share some exciting news there (I think they will announce after the Guilty Gear Strive finals that Sony acquired Arc System Works)
Sony will have the EVO finals from August 13th to Agust 15th and at the end of the tournaments the fighting game publishers traditionally make some fighting game related announcements. I highly doubt Sony would make a big ass event just before EVO with announcements that would keep the attention out of EVO.
For the reasons I mentioned above (specially because of the GT7 and Abandoned ones) I think it will be July 29th. And if not, I think will be August 5th. Basically a month after the previous State of Play and providing enough time to don't steal attention from EVO.