So upgrading to Internet M will not bring additional speed from the copper line.
But, with the booster there is up to (around) +80Mbit/s additional speed possible in the down. So if your copper line has 40Mbit/s, you can reach up to 120Mbit/s with the booster. (Depending on load and capacity on the 4G/LTE antenna. On your Booster screenshot, I see that you don't have much signal strength from the LTE antenna (just -103dBm)
Note: The speed increase with the booster is usually very variable and only in rare cases at 80Mbit/s. Usually it is much less than half. Even less with a low antenna signal.