Fan table/curve based speed contol is the only option left now for such cards with new drivers, fixed fan speed control is gone and can only be emulated by setting 'flat' curve. AMD traditionally corrupted (intentionally removed?) fixed fan speed programming API (Overdrive 5 compatible fallback path) for old Overdrive 7 GCN GPUs in 22.5.2. Found old PC with rusty Ellesmere (RX470) GPU in nearby area to peek inside the reasons, that's the only thing I can offer.