The RTX 3060 is still a solid 1080p card, so do not replace it on reflex for GTA 6. Nobody has an exact FPS number yet, but you can still get a clear keep-or-upgrade answer from a planning check.
For the predicted 1080p target, treat the RTX 3060 as a keep-for-now card, not an automatic upgrade. Only shop for a new GPU if the check points at graphics, and only after you have ruled out CPU, RAM, and storage.
Do not buy on a guess. Check your exact setup in 60 seconds and see the one part that matters.
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.
predicted:FrameReady Can I Run tool. FrameReady uses predicted PC targets until official PC requirements or measured benchmarks are available.