It doesn't look good given there was a whopping 3 month gap between patch 3 and patch 4. No idea about the release date but considering this abysmal update rate its definitely not going to be in 2021.
If I recall correctly, only a small percentage of Larian's team was working on EA, about 10%, while the rest forge ahead and work on act 2 and beyond. And it was, I believe, a 2 month gap. (Patch 3 launched December, Patch 4 launched February.)
