If you put everything to absolute lowest, with DLSS set to performance, at 1440p, FPS will sit at like 90-100. Really hard to even see what sliders have any affect on performance, cause the max settings will sit at 60, that's full psycho RT and everything. This is with a 3080 and 12900k. Same with a 5900x and a 3080ti.CPU bottleneck is often the cause of lower FPS in areas with a lot of NPCs. The 3070, assuming it is the desktop version and not a laptop, should be plenty powerful enough. You may want to try setting the graphics preset to Ultra and RT ON but on Medium and DLSS on AUTO. Those settings work for me on an RTX 2070.
If you're going all in, here's the high-end machine we'd recommend building or buying for Cyberpunk 2077 at 4K: Processor: AMD Ryzen 5 5600X ($299) RAM: 16GB Corsair Vengeance LPX DDR4 3600 ($72
TmIHKIK.