Q: If a suspension issue comes up later, can Tesla blame my UP-03 wheels?

No, fitting aftermarket wheels alone is not grounds for Tesla to deny a claim. Under the Magnuson-Moss Warranty Act, a manufacturer has to show that a specific part caused a specific failure before denying that claim. A quality forged wheel that uses factory hardware and hub-centric fitment gives them little to point at, and keeping your install paperwork alongside correct torque specs protects you if the question ever comes up.