Resolution sets the whole hardware bill. The same PC that clears 1080p can fall apart at 1440p once the GPU runs out of headroom, so pick the target before you pick parts.
Plan around 1080p until official specs or benchmarks land. Only step up to 1440p if the check shows real GPU headroom and you actually own a 1440p screen. Otherwise you are paying for pixels you cannot use.
Do not buy on a guess. Check your exact setup in 60 seconds and see the one part that matters.
predicted:FrameReady Can I Run tool. FrameReady uses predicted PC targets until official PC requirements or measured benchmarks are available.
official:Rockstar Games GTA VI page. Rockstar lists GTA VI for PlayStation 5 and Xbox Series X|S. FrameReady does not treat PC requirements as official until a PC source exists.