@SimoneB The 555 motors are >3A so it's possible at start-up or if it stalled that it exceeded the max current of the MOSFET and caused it to fail. You can use a 5V controlled relay to switch the motor (some boards have these) and then the motor is not a problem. A Dremel would be good.
@firewirehn Normal TTL convention is high is ON and low is OFF, the laser you showed is opposite which is really dumb. So it would need a TTL logic inverter on the input, you should also include a pull down resistor for safety. If you don't have electronics experience I would just purchase a better laser like the Eleks brand that is plug and play with their board.
@Bill-Thebert T2Laser does not create inlay (offset machining), it is for engraving or carving only. It is easy to generate a DXF with these profiles, and you could also add the hatch fill to remove the material. I believe Inkscape would let you do this although I don't use it much so perhaps someone else can confirm.
You appear to be missing the most important step, click the CNC Mode to enabled it (check mark next to the menu item), it will request the maximum depth. All units are mm as that is the Grbl default.
@firewirehn OK, so if you do not have homing switches you must disable that function (if you enabled it). If the house icon is red you have enabled the feature without having the hardware required, so go to the settings menu and disable home switches.
You can then right click the house to set work piece origin (0,0), this is where it will start and finish the job. This position will be remembered until you exit the laser controller screen. So leave the laser at 0,0 when you exit and it will keep the location when you return.
@woppie09 I'm not sure I understand your problem or question. You are using T2Laser with my Grbl 1.1e DEFAULT firmware? It should work correctly with the EleksMaker laser, you can adjust the resolution (quality) to get the finest detail.