My Mac is not turning on but has weird signs

I was using my MacBook and the screen suddenly went black. A few seconds later, the keyboard, Touch Bar also turned off. The computer doesn’t turn on anymore but weird issues are present:

• when the charger is plugged in, I can hear the charging tune
• when I “turn it on” nothing happens except the trackpad becomes clickable
• when I “turn it off” (by holding the power button) the trackpad blocks
• when I “turn it on” in safe mode (CMD-R) only the “esc” key on the Touch Bar turns on…

I have also tried to connect the computer to an external monitor and the screen seems to flicker. Any ideas what could be the cause of the problem? Thank you a lot in advance.