That is absolutely false.I can confirm that the cable bundled with PS5 is "High Speed HDMI Cable", our media company (Wirtualna Polska, and two of its tech websites: dobreprogramy and polygamia) is in possession of 2 units. High Speed HDMI Cable can't support 4K+120 FPS. It is absolutely impossible. Although it is possible that HDMI 2.0 can support HDMI eARC, VRR and Auto Low Latency Mode (which can be optionally added to HDMI 2.0). And probably some misinformed people took this information about HDMI 2.0 being able to support some HDMI 2.1 features for granted and thought High Speed HDMI Cable can support 4K+120FPS. Once again, I'll confirm - it cannot.
2.1 cables are physically and electrically identical to 2.0b. They do have tighter impedance-control tolerances. Some cable were already compatible and they just needed recertifications to be marketed as 2.1 compliant.