What's really going to make the difference is setting ray tracing to high instead of ultra, and keeping reflections on medium. The 4070 handles maxed-out settings no problem, but the bottleneck is those ultra ray tracing options that eat up tons of GPU without you really noticing much visually. Making that change you'll easily get 70-80 fps at 1440p without sacrificing the quality you see on screen.
But there's a trick most people overlook: use DLSS 3 with Frame Generation. It's not just upscaling, it generates full frames in between. With that set to quality you're gonna get almost ridiculous fps numbers and the image will still be sharp. That's where BG3 really shines with your card. The difference between that and playing without DLSS is night and day, especially if you leave ray tracing on high.
As for whether it's "worth it" to max everything out, it depends on the player. Some people notice the difference between medium-high and ultra, others don't see anything. But with the 4070 you're not sacrificing performance by cranking up the graphics, so at that point, why not? Just don't be a purist about ultra ray tracing, that's all.