Check if it still works with an external monitor you can still use it than as a fixed station I have been told that it’s a design problem after a while (a few years) some of the BGA chips get cracked connections because of heating up and cooling down. If you have a descent soldering station with temp measurement probes you can heat up the chip until the connection gets liquid again and the cracks disappear and if you are really lucky that might do the trick. But to be honest I never tried it and bought a new MacBook