AVR Freaks

Thank you, I'll try that and comment here if a solution is achieved.

Edit: I must say I'm having a hard time trying to find the support ticket system

I got help from the microchip technical support team, the value for the LORAWAN_STATUS attribute is not in the SAM R34/R35 Microchip LoRaWAN™ Stack Software API Reference Manual

However the information can be found in the "lorawan.h" file inside the MLS code for SAMR34/35:

/* LORAWAN Status information*/
typedef union _LorawanStatus
{
    uint32_t value;
    struct
    {   /* If set, the network is joined */
        unsigned networkJoined :1;
        /* determines the state of trasmission (rx window open, between tx and rx, etc*/
        unsigned macState :3;
        /* If set, ACK and uplink packets sent due to FPending will be sent immediately */
        unsigned automaticReply :1;
        /* If set, adaptive data rate is requested by server or application */
        unsigned adr :1;
        /* If set, the Mac command duty cycle request was received */
        unsigned silentImmediately :1;
        /* If set, the mac Pause function was called. LoRa modulation is not possible */
        unsigned macPause :1;
        /* If set, data is ready for reception */
        unsigned rxDone :1;
        /* If set, linkCheck mechanism is enabled */
        unsigned linkCheck :1;
        /* If set, new channels are added via CFList or NewChannelRequest command or enabled/disabled via Link Adr command */
        unsigned channelsModified :1;
        /* If set, the txPower was modified via Link Adr command */
        unsigned txPowerModified :1;
        /* If set, the number of repetitions for unconfirmed frames has been modified */
        unsigned nbRepModified :1;
        /* If set, the prescaler has changed via duty cycle request */
        unsigned prescalerModified :1;
        /* If set, the second receive window parameters have changed */
        unsigned secondReceiveWindowModified :1;
        /* If set, the delay between the end of the TX uplink and the opening of the first reception slot has changed */
        unsigned rxTimingSetup :1;
        /* If set, the device must be rejoined as a frame counter issue happened */
        unsigned rejoinNeeded :1;
        /* If set, Multicast frame reception feature is enabled */
        unsigned mcastEnabled :1;
    };
} LorawanStatus_t;

Thank you to the technical support team, and thank you HKPhysicist.