I don't think BG3 will ever have RTwP. The way i see it is that the number of encounters in DOS2/BG3 are limited and it was designed for turn-based. With RTwP combat may resolves or complete much quicker and perhaps making DOS2 a much shorter game especially there's no trash encounter.
I think that's one of the reason perhaps Larian will never put a RTwP in it? Just my observations.