When the AX53 is set to WPA2/WPA3 mixed mode, PMF (Protected Management Frames, 802.11w) is required for WPA3 clients and optional for WPA2 clients. That means WPA2 devices can still connect even if they don’t support PMF, while WPA3 connections always use it by default. If you want PMF enforced for all clients, you’d need to use WPA3-only mode - but keep in mind that some older WPA2 devices may no longer be able to connect