Pls. consider that Couch Coop is great for many console players wanting to play together without a second device.
Probably not the highest priority feature, but not that hard to code or test either when a game is prepared for it.
Will BG3 have this feature, either in Aug at release time or added later?
I understand this is not a primary release date concern, but it certainly is a Booster to anything sales on consoles.
I'd love to have it on PC, as there is few gamnes who suit it and I love to play split-screen controller coop games on a projector.
Split-screen is big for diggimng all the quality time together with your GF. BG3 is about realtionships after all. So the extensive captivating storyline shouldn't kill them in real life.